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Building Tips and technical articles. => Building techniques => Topic started by: Dave_Trible on May 10, 2013, 08:33:33 PM
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I had committed myself to do a build thread on the Sterling Spitfire and I will but with recent events I'm moving that build down one knotch and going to build another of my Desperado airplanes to replace the one I damaged and retired. I started cutting wood when it occurred to me I could try adding this new dimension to the process and I might show some of my methods which to some are different and perhaps strange but that's what this is about. So grab some popcorn and settle in. I'm working from an Iphone and struggle at times to crop the photos down to the size I can upload here. For that reason I have found I can only send one shot at a time and my inputs may seem choppy.
The first shot is showing that I have made 1/16 ply root and tip templates to make the rib sets.
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Next I'm making the leading edges. These consist of an edge and an identical cap which is put on after sheeting. These are 3/16 x 7/8 and are router cut using a 3/16 plywood template to which balsa blanks are taped with double sided tape and run on the table router. I get perfectly straight edges this way. The spars are laminated and made the same way. The trailing edge is just very straight 1/4 sq.
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Edges are spar laminations cut and ready to be glued up.
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I've taken the root template and traced off 24 blanks from 4-6 # balsa.
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Now drilling two 1/8" holes in each blank for bolting a stack of blanks together for shaping. All for tonight.
Dave
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Dave,
Build threads are fun to do until someone points out something dumb you did. Then not so much. LL~
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Dave,
Build threads are fun to do until someone points out something dumb you did. Then not so much. LL~
Randy, now how would you know about that,, I never say anything like that on your build threads,,
well unless you said it yourself,, D>K
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Build threads are fun to do until someone points out something dumb you did. Then not so much. LL~
I dunno. I find the pain of screwing up publicly and getting it pointed out before I bury it under other work is less than the pain of un-building down to the screwup.
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Dave,
Build threads are fun to do until someone points out something dumb you did. Then not so much. LL~
You guys are too much! Let me assure you, if I screw up it will be completely intentional.
Dave
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Well #+>!%%. I've tried this morning to upload another photo but the server refuses to take it so I'll try later from work. I love technology.
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I brazed up some 1/8" music wire control horns. Back to finish later.
Now it's seeing double.
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Multitasking. Still finishing the take-apart Desperado. Here parts hanging to dry.
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Thanks for the photo build of the new plane. As far as pictures I have problems also when this new fangled electronic gadgetry decides it doesn't want to work. And then all of a sudden you realize you have made three posts of the same thing. What is exasperating is trying to remember what size the pics should be for each forum.
Well the weather is sunny and warm outside, but it is windy. Need to get back on that elm tree.
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Drives me nuts John. I crop all pics to the same size and one goes another doesn't. Seems worse with white backgrounds and closer shots. I'll figure it out I guess.
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I like a guy that a guy that makes his own horns. Cool.
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Here I've bolted half the rib blanks between the root and tip templates ready to carve and sand.
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Drives me nuts John. I crop all pics to the same size and one goes another doesn't. Seems worse with white backgrounds and closer shots. I'll figure it out I guess.
It's the file size -- some of the ones you're trying to upload are HUGE, and there's a 1MB limit.
You need an app that resizes photos. There's supposed to be photo resizing sites out there, but I know nothing -- I know nothing at all.
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Yeah Tim I'm catching on a little but my cropping ability on the phone is limited. Funny but that last photo wouldn't go at all...until I logged out and then back on. Then it did fine. We'll struggle along.
Dave
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Here I've bolted half the rib blanks between the root and tip templates ready to carve and sand.
When I stack sand ribs I do both sets together. I separate everyother one for inboard and outboard sides. Thus leaves less of a angle on the rib.Us rib 1,3,5,7,9,11 and ribs 2,4,6,8,10,12 etc. outboard. My theory is the slightly thicker panel inboard creates more lift.
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Robert, you got lonnngggg bolts. D>K
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Robert, you got lonnngggg bolts. D>K
Ace hardware sells all thread
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I hadn't thought of that but has merit. Not going to get much done today or tomorrow . Long work hours and will welcome a new grandchild into the world on Monday. (#3, a boy). Might squeeze a little shop time later tonight. I bought a couple new glues to try so I 'll share the info. Ordered wood for about two more airplanes so I 'll be busy!
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Stole away a couple minutes to sand the first stack down. Notice I marked center lines on both ends. These will allow me to extend centers on each rib which I'll use for alignment as I assemble the structure in the wing jig.
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Having shaped the stack now I unbolt them. Some have mentioned the sanding taper. This is how I get rid of it. Slide all the ribs nose down on the table-flush front. Put the template back on with tape, sliding them back just far enough to expose the taper on front and sides. Now simply sand it off flush with the templates and no more taper!
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Now the spar slots.......
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And I number them right away lest I screw up and mix them up. Next I'll draw center lines , open and cut whatever spar slots and openings and lightening holes wanted.
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OK I'll close tonight with something to think about. The pic below shows two full stacks of ribs for 60" wings and aren't exactly the same but very close. One stack has yet to have any lightening holes cut, the other set has all the normal cut openings. What's the difference in weight? .2 ounces! I've found issues lately with crushed ribs in a couple wings caused simply by tight silk span and dope. Flying would have to cause more damage with flimsy ribs. You'll see on this one I'm doing very little lightening of the ribs. The whole set complete without holes is under 1 oz. I'm keeping the strength with very very little added weight. Has to help keep the wing straight too.
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Short night tonight, just a frame or two. I'm showing a plywood guide I made to mark the spar opening very accurately . This is faster than anything else I know. I only saw cut the start point with the templates on. My spars are laminated and vary in thickness at differing stations. That makes it impossible for me to completely saw cut the slots in a stack.
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I've laid out the plans and placed the ribs in their respective spots. I can then lay down a straight edge and mark the approximate lead out location on each rib so I can cut the hole accordingly. These will be slotted to allow lead out adjustment fore and aft.
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The next couple days will be about building the wing jig. Here is a place where I wonder far off the prevalent reservation. Why? First it's what I'm accustomed to and because I think I retain the best control over the trueness of the finished wing this way. There are other good methods- this is mine. It's sort of a truss system so I start with cutting truss pieces. It will develop so be patient. The first thing is router ripping the leading edge truss material from medium 1/4 balsa.
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Next I take that perfectly sized strip of lumber and cross cut into separate parts to be glued on the wing board.
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Seems you're humming right along.
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Randy I'm trying. Next shot shows the Stunk Works wing board. On the rear is a 60" aluminum rule screwed to the board. Then I've screwed a piece of 1/4" balsa to that at the right height off the board. This gives me a perfectly straight vertical wall to which I can pin the trailing edge to.
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This opening in the wall and the four alignment blocks are for the take-apart version as the wing and fuse have to be built together. These are not use for the one piece airplane.
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Glueing on the leading edge trusses at the right spots and checking to get them vertical.
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A pleasant visit, grandson Dylan and his dad Kevin came for din and shop time. Dylan hold his new Ringmaster Jr. w/ Brodak .15. Will fly it in basic event at Topeka Memorial Sunday.
By the by; that IS his AMA number. It was my dad's number (his great grandfather). AMA was so kind as to give it to Dylan upon my request. Maybe when Dylan has kids.......
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The wing jig is now ready for biniss'.
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Not sure you can see the pencil marks but I previously laid the leading and trailing edges on the wing plan and marked exact rib locations.
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Assembly begins. The trailing edge is nailed down atop the rear wall. The leading edges are pinned on their forward trusses and root- tip ribs are pinned in. It's now a matter of pinning in all the remaining ribs but NOTHING is glued yet.
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Almost forgot. These are 1/16 ply rib doublers for the landing gear ribs 3 and 4. I didn't use these on the first couple of Desperados which may help explain the damage to the first one.
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A different approach to wing construction. Your grandson looks great with his plane. Also your Dad would be proud of you. He is still missed by me.
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A different approach to wing construction. Your grandson looks great with his plane. Also your Dad would be proud of you. He is still missed by me.
Thank you John. You were always one of his favorites. We all miss him. He'd get a kick out of Dylan. Attaching a photo I have in my living room. This is dad with his Korda wakefield on the Kansas prairie in summer 1941. Four years later he would sit in Bad Orb concentration camp after being captured in the Battle of the Bulge.
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OK now a very critical step. All the ribs are pinned in. I'm going to check for any twists in the wing and shim under the leading edge to true it up. Notice the Robart incidence meter sitting on the motor mount stock. I'll check every other bay. You will see the meter a bunch here. I use it everywhere because it never lies to me. Won't build without it. Only when I'm sure it's all straight do I glue. Then I walk away overnight and let it cure. Spars will be put in tomorrow.
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Interesting methodology.
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Back in the shop finally. Tonight I'll start by laminating the wing spars. Anticipating a question about why I use tapered laminated spars, I'll tell you I've done this going back to Music in the 80's. It had to do with trying to get the most strength where it was wanted but pare off whatever unneeded weight I could. I long ago forgot the equations and parted with my engineering manuals (and it doesn't matter) but I was considering span loading. The types here are supported and unsupported spans. Our planes are sort of both. In the air the wings are not resting on static points or a fulcrum so it would be called unsupported. BUT to a greater or lesser degree it IS supported along the span on a blanket of air pressure. From an engineering standpoint there are separate formula for both to figure structure requirements. Since I try to think worst case scenario I consider the airplane in a hard bottom corner at 10 Gs. Not sure how good that number is but it's been used as a basis for our discussions for years. That would then equate to resting your 65 ounce airplane between two chairs on the wing tips or last rib then applying 40 lbs on the fuselage! WOW! What is obvious is that the highest stress is right in the center, tapering to zero at the extreme tip. (Remember that airborne those tips have no pressure point- no chairs). So to put spar requirements in line with where loads are imposed one would beef it in the center and taper it to zilch at the tips where next to nothing is needed. Common structure here might be 1/4 square spars. Given our criteria I'd think 1/4 sq. is two light in the center for, say 5000 load flexes before failure and surely too heavy at the tips. So my spars taper in steps along the span in the horizontal ( constant vertical) from 3/8" square at the root to 1/8"x 3/8" at the tip. It's always worked so I continue the practice without further thought.
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I've gathered the stuff I need and will work on a 'pin able' board topped with waxed paper. I've precut a stack of very straight 4-6# balsa strips 1/8" x 3/8". I'll super glue (ca) these together layed along a straight edge.
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Here I've put down the full span 30" lams then glued on the front 20" lams. I'll turn these over and put the third 10" and last lam on the back side.
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Spars in and glued.
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Trying some new glues here thinking Sigment replacement. Up till now I've used the Beacon 527. It seems exactly like Sigment. I'm using the new Quick Grip by the same company on the spars. It looks and smells the same but shows a little foaming like Gorilla brown glue. The Loctite GO2 glue acts like the Quick Grip but has a different odor. I'll follow up my thoughts on these.
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I use an upper and lower bellcrank platforms which double as spar doublers in the center. These are 1/8" hard ply- never lite ply!!!!
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A busy area. Here the bellcrank platforms and leading edge doublers are epoxied in.
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Tonight I'm going to make a couple bellcranks and put on the leadouts as its nearing time to put it in. I make my cranks from 3/16" Delrin. This is a super tough self lubricating material that just doesn't wear out. It's not cheap. The sheet you see was 12"x 48" when I bought it and was something over $100.00. However this sheet will last the rest of my natural life. You will see a bellcrank pattern and the screws I'll need to attach the cutting pattern to a Delrin blank. I doubt anyone here is going to set up to manufacture Delrin cranks but I'm showing how I do this just for your interest. The blanks are hard to cut even on the scroll saw.
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The final cut is made on the router using a diamond bit.
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I've whacked out two Delrin blanks on the scroll saw and have screwed the pattern to the first one.
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The router cut. Dang that's loud!!
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Sizing the threaded aluminum bushings.
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Drilled, bushed and ready to go.
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Now we spool off some .027 from MBS supply to make leadouts.
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The double loop lasso . Can only pull tighter-never loose and gives a secure backup loop should one ever break. With Delrin over 2000 flights have been logged on one airplane done as shown with ZERO visible sign of wear on crank or cable.
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I wrap a layer with fine soft wire then CA on the under wraps..
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I then fold back the little tail of cable, rewrap and epoxy the wrap. Now the unit is ready to be installed.
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Slogging along here tonight I'm starting the top sheeting with the rig still nailed down. I needed to move the pins holding the trailing edge down from top to side to get them out of the way. I glued in a piece of sheet between the ribs to support the joint of the trailing edge sheet.
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Split a sheet of 1/16" for sheeting....
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And glueing it on with 527 since I need work time.
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Before I put the leading edge sheeting on (this will be open bay) I need to sand a chamfer in the leading edge so I'll mark a guide line on the edge then apply clear packing tape over the ribs to protect them while I sand. It is pretty hard to sand through that tape.
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How the chamfer looks..This shot also shows how I had to shim under the leading edge to raise the edge up. That's what the incidence meter told me to do. It tells me the wing board has warped a little and without using the meter I'd have built a twisted wing and not understood why since I'd built many good wings off this board. The meter is king!
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I mentioned I'd be trying some new cements. The Quick Grip is strong but is a little too thick and globs. It doesn't seem to soak in and smooth out in the joint. Notice the glue on the spar joint. It foamed up a little then becomes a chewy glob. Setting this one aside.
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Thanks Dave I will mark that one off my list. Your build sequence is different I must say.
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John that's what I've been saying about every else's building sequence for years....this morning I'm going to get all the sheeting and cap strips on the top side then set it aside to dry so I can sand and shoot a grey coat on the take-apart airplane which has been just sitting for days. Lets see how far I get. The first shot shows the center web sheet joiner for the LE sheeting and that I got the chamfer ready on the LE. Bellcrank in loosely.
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Leading edge sheeting on using 527 for working time. I'll do the cap strips with Gorilla CA for speed and less weight.
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I hope you can see this. This is my stripping table which is obviously multi purpose with all the dope drips and spatters. One stationary rule (rigged on pins so it can slide up to run wood under) and a second aluminum yardstick which can slide sideways but be screwed down to create whatever space I wish. Set here at 1/4" to strip out cap strips.
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Last entry for now, the sheet and cap strips are on the top side except the center section which I'll do after the wing is done and controls inside done. Next I'll turn it over and re-nail it down a little differently to the jig, install the landing gear and such, then sheet the bottom.
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I would have bushed the leadouts, but if you are happy that it won't wear they it's less weight. I use a horseshoe end with inserts.
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Hi Randy. If I used most anything other than Delrin I would agree. I've used these for over twenty years and (dare I say it ) my cranks have been in several other Nats and Worlds airplanes with never a failure.
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What can I say, I'm paranoid. Belt AND suspenders guy.
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What can I say, I'm paranoid. Belt AND suspenders guy.
However you keep it together is fine by me Randy.
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OK a couple more shots before I move the board off the table to work on the other plane. (took a break to run to the casino to get my daughter some chips for her birthday- the license plate on her SUV says CARDPLAYER so you get the idea. Dropped $100 on the silly bandits and came home to the safety of the workshop).
Wanted to show sanding the sheeting flush with the leading edge for the next step- spot glueing the leading edge cap on to create a ledge to lay on the trusses when I turn it over.
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And here is is with the cap on.
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Shot the first grey coat on the other airplane and am still standing so I'll go a couple frames. I've pulled the wing off the jig and now need to remodel it a little to flip and remount the wing. Before I put the leading edge caps on the wing I marked where the leading edge sat on the trusses. I need to trim the trusses now to clear the curvature of the airfoil. The caps will rest on what's left after I add 1/16" shims to elevate the front on pare with the trailing edge after adding the sheeting there.
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Quickly done with the cut off wheel in the Dremel and the knife.
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The shims from extra cap strips CAed on and ready to nail the wing down.
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Like this..
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Most times I simply pin the cap down on the trusses but this time I'm spot glueing it to get pins out of my way. The granite slabs weight it down till the cement dries.
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Lookin good Dave!
See you at the Nats!
Derek
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Had a few minutes before heading to work so...Got the wing nailed down, the TE sheeting on, the LE chamfered. Now I'm using scrap balsa to fashion a pattern for plywood landing gear platforms. These have strange angles so I pattern them so not to waste the expensive ply. I heard there was only one actual supplier left who makes it. It's common for most to use removable gear. My take-apart airplanes do have removable gear for obvious reasons. I put removable gear in most everything for years until I came to the conclusion that 1. I never took it out. 2. It was 'messier' around the gear and 3. It weighs 1-2 ounces more to make it so with blocks and fasteners. Given that I'm keeping my solid wing ribs and dispensing with the removable gear. I also do use 5/32 wire gear. These birds aren't Noblers and I fly off pretty rough turf sometimes. I've bent 1/8 wire gears on washboard landings.
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Off work today so tried to get out real early for more test flights on the newest Desperado before the wind came up. I seemed too late as the breeze was already coming up. The grass was also really deep too but the mowers were working today. Did go ahead and fly once and think the new one will trim out OK. Now I think I've got two new decent airplanes to trim and work with. That takes a little pressure off.
The take apart ship has some patching drying so I thought I'd work more on this project. This one might slow down progress some because as weather improves I'll be transitioning to more flying time and less shop time. I'm also going to push the take apart project along so it will be ready to fly before the Nats if its needed.
The place I'm starting today is to make up the landing gear and get it installed.
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Measure it out. Recently I had a bad drawing and made the gear a little too short. Sanded the prop so decided to lengthen the gear . I had to braze on extensions right on the bird which was interesting. Not to be repeated.
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Bending the 5/32 wire is a lot easier with the bender I made.
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Kevin came over. Here he is working on his Ruffy.
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Here he is using my other wire bender to do the LG for the Ruffy.
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Wanted to show the platform and gear ready to sew with soft wire.
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And now epoxied in.
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Dylan's contribution to shop night at Grandpa 's.
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That is a looooong nose for sure!!! LL~
Marcus
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Grandpa to the rescue!
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Yaw Mon!
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Good news- my hobby shop phoned this morning to say they got Sigment in. Going to buy em' out. Hope to get back on this build soon. Put the last clear coat on the take-apart bird this morning and may test fly it this week.
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Awesome ship.
Congrats!!!!! #^
Marcus
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Thanks Marcus. Never know for sure what you have till you fly it. I'm thinking Wednesday morning......
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Well call me fickle. I've decided to fix my number one Desperado since I think it still flies best at this point. Not going to get enough flying time to really trim out the other two new ones well and get much serious practice. If need be I'll slap on the zig zag turbulators. I put carbon inside across the split top sheeting. When that dries I'll slip the gear back in. Sure wish I'd have put the plywood rib doublers in this one.
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Up on its legs and on the road back. Had some of that blasted dust from who knows where inside the canopy so I decided to take the opportunity to pull and change it. I'll likely fly this one by mid next week.
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Des 1 back in service!
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Cool!
Marcus
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So... What do you do when it's too windy to practice? Build a new fuel tank. I started this a then thought maybe a few hadn't done this before and might like to see it go together. I'm not too worried about how pretty they are, only how they work. My tanks are different (you've come to expect that from me) and run very consistent from start to finish. Making my own also allows me to size and shape it just how I need it to be. For my .61s I use the tanks shown built in the photo. These have been used and removed from other airplanes and will be reused. These are 7 ounces. I am fitting my .76 (John Deere) into my newest plane and need mo gas. I'm building an 8 1/2 ounce tank of the same design.
Externally points to notice are the slant on the front of the tank and the pinch on the back corner rather than a full length wedge along the outboard edge. The slant is to run the tank up under the pipe header to grab a little more capacity. Likewise the pinch at the pick up corner maximizes the tank capacity in a given space. The noses on my planes are about as short as I can manage so space is tight. For Desperado I can only get the 8 1/2 ounce tank in the take apart version where no wing passes through the fuse so it can extend a little further back.
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You can see I've made a tin blank which will make the top, bottom and inboard side of the tank. I'll bend this and make the side cap. (Then move it out lest I be late for work!)
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A few more steps tonight. I'm using a couple motor mounts as a bending tool for the tin.
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Here I've laid out and cut the blank for the outboard side.
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Here we've cut slits around the curves for bending.
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All bends are made and the masking tape pulled off.
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Now clamping it together for soldering. I'll first tack a few spots then continuous solder down the straight joints stopping just short of the curves. I only use fine rosin core solder (electrical) for this. It melts a a little lower temp but most importantly acid core or silver bearing solder leave corrosive flux behind that will eat up your work in short order no matter how you try the clean it. Just don't use them.
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Once the seams are soldered on the straight sides I turn and solder the inside of these butt joints too. Until I started doing this I've had a couple seam leaks right here where no lapping metal existed.
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Each side around the curves is pulled in and soldered.
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Tadaaa!
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Butting the front down on fresh tin to trace the front cap.
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Add some around the edge for a flange, cut and nibble the corners.
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Fit and solder.
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Hi Dave,That tank is lookin' real good.Sure is nice to get a custom fit in an off the rack world.I'll be at the Nats in a couple weeks,maybe I can take a look under the hood?See ya there,Trax
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Nice work!!
Marcus
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Thanks guys but we got a ways to go. Marcus I can always count on you paying attention. Jeff we will sure spend time at the Nats and you can rattle under the hood there.
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I'm going to do a little plumbing tonight. I've learned the hard way to use ONLY COPPER tubing for fuel tanks. Brass is common but corrodes in our fuel. If you don't trust what I say put a small piece of brass tube in a jar with a little fuel. Leave it set a few days and watch what happens-green slime. I anneal my copper by passing it through the flame on a propane torch very slowly. The copper should just start to glow a little. Use pliers on both ends. Lay the hot tubing on a safe surface and allow to cool slowly. It will be black with scale but sand it clean with 400 grit paper and wipe with acetone or alcohol. This will make the tubing softer and easily bent without kinking.
I put masking tape on the tank where I need to drill holes and marked the locations.
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Holes drilled.
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Dave
I like building threads I can learn from.
Thanks for posting
Marcus
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Tools. Here I use a cut off wheel in the Dremel to cut the tubing. Also use a large soldering pencil. Trigger guns are , well, just not serious......
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I've beveled the end of the pick up tube so it won't somehow become restricted by the back cap or solder. I insert the tube in the front cap and push it about as far back in the tank as I can. This eliminates most of the burping at the end of the run. When we get to it you'll see I place the end of the uniflow tube very near this same spot with little distance from the end of the pick up. This negates most all the lean out at the end of the run. No three laps of scream. Just a few seconds of speed up and a clean cut off . Anyway, I solder the pick up in place inside so it won't move or flop around with vibration.
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Now the 'secrets' to my tanks. You'll see I've taken what will be the uniflow line and 1. Beveled the edge sharply and 2. Cut or filed a knotch in the very end. It will develop.....
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I'll close for tonight with one more shot. I've bent the uniflow to its approximate shape and laid it on top the tank in its position when installed in the tank. You can ponder what you are seeing while I get my beauty sleep.
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At this point I want to touch on my line of thinking about uniflow design and placement. What I'm showing I've used since the ST.46 days with very good results. I get frustrated if the airplane speeds up noticeably through the pattern. There are a few engine issues that could cause that but it's usually tank design. I have seen guys fiddle and fiddle with engines, fuel, props, plugs when the real issue was the tank.
The desired result is to provide a blanket of air pressure to replace depleting fuel and push on the fuel for a more consistent fuel head at the Venturi. What I see as problems are 1. A uniflow line that is placed in a way that centrifugal force pushes fuel back up the uniflow line restricting the easy flow of air down the line. Think of the stopped up kitchen sink. Nothing goes down when stuff is coming up. 2. Placing the end of the uniflow line such that it is no longer submerged in the fuel at some point in the run, letting go the pressure head you've built up in the tank. This drops the head at the Venturi and engines goes leaner. This is the bit about screaming laps at the end of your flight.
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Given these things my answer is the uniflow line you see. You'll see that centrifugal force will throw fuel OUT of the line helping draw air in. The line arcs up out of the fuel in such a way that the fuel would have to run up hill to come up the line. The end will be soldered directly on top the pick up tube right near its end. The uniflow bevel will be turned away from the pick up opening to block air bubbles from going directly out one and in the other. Instead it bubbles to the air pocket on the inboard side and stays trapped there until the very last few seconds of the run when the end of the uniflow is exposed.
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Dave I have used a sharp pointed punch to make the holes in my tanks. It give a little meat or solder. Sometimes I may even put a washer over the tube for more vibration protection. I like your tank design. It reminds me of Rabe's tanks.
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Dave I have used a sharp pointed punch to make the holes in my tanks. It give a little meat or solder. Sometimes I may even put a washer over the tube for more vibration protection. I like your tank design. It reminds me of Rabe's tanks.
John I've sure poked many tank holes before but I tend to get heavy handed and gorge out holes way too big. Drills are safer for me.
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Getting set up to solder in the uniflow. Now you can see why the bevel and knotch in the end of the tube. I'm setting the tube about 1/8" forward of the end of the pick up. You might also notice I ran the uniflow up to the top of the tank then turned down to exit the bottom. This is simply to not allow fuel to gravity drain back out after filling.
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Soldered in place.
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Now I've soldered the other end at its exit along with the overflow, which is capped after filling the tank.
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One last look inside. You can see the overflow way in there running up to the top front corner to get max fill with the airplane sitting normally on the ground.
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Now I'm going to pour in a couple ounces of acetone and shake it around a minute to loosen the rosin flux and dust. Then just pour it out and let dry while I fashion the rear cap.
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All soldered up but one more step....
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In the tank submersion test vessel- bread pan full of water. Blow test looking for bubbles/leaks.
This job is done. Ready to install. Making tanks isn't tough and you should try. They might look crude but you get better with practice.
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Ouuuuu... Dat tight!
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Tank looks great Dave. The punch I use is out of the old school compass we used to use to make circles and arcs.
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Des 1 back in service!
Hi Dave,
A truly "professional" repair you did there! When you cannot tell where the damage was, it's truly well done.
BIG Bear
RNMM/AMM
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Thank You Bill! Just glad to have the bird back. I think it's the Nats ship as of right now.
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Thank You Bill! Just glad to have the bird back. I think it's the Nats ship as of right now.
Best of Luck at the NATS, Dave. I can only "wish" I could be there this year...........
BIG Bear
RNMM/AMM
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That's as custom-fit as one can get...
Looks great too!
Marcus
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Outstanding!! Kudos!!
Great workmanship and the photos are excellent also.
A Grand Slam!
Charles
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Thank you guys for your kind comments. Getting this one ready for the second half, the team trials. I'll test fly it as soon as I get back from Nats. I'm already wondering how that .76 will feel in a 650 sq in airplane. May have to tie myself to a stake in the ground, but I should cut this d#&$ Kansas wind.
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I have a little time between practice sessions so maybe can do a little on the original project of this thread. I'm digging a few hardware parts out of a hangar queen to reuse and save time. I had made a point early on about cutting lightening holes in soft balsa ribs to a fault. When I cut away some covering on the queen (Desperado #2 which was subject to too many design developments) I found exactly what I was talking about earlier. If you look closely you'll see how just the tightening silk span crushed the ribs and altered the airfoil shape. This is why I'm leaving the ribs solid with the minimum lead out clearance.
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Back on the building board I sheeted and cap stripped the wing and left to dry overnight. This morning I lifted the wing. I removed the first cap I tack-glued on the leading edge and squared off the wing and tips to receive the 3/16 final cap. I left it wide and will trim it later.
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Cap being applied.
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Out of the queen I got the tip weight box which I mounted in the new wing. It's made of pieces of motor stock to hold screws and 1/16" plywood.
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Here the bellcrank has been installed. It is suspended between the two plywood platforms. The pushrod is retained with a wheel collar-not soldered. Now I will JB Weld anything in here that could work loose. Over the years I've had two cases where the nuts screwed down tight on the bellcrank and bushing causing heart surgery in the airplane. That's what taught me to JB the works. Never a problem since.
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I finished the center section sheeting and put the wing tips off the hanger queen on it. It's set aside to dry and now I'll start the stab/elevators the old fashion way of wax paper over the plans. I know Ty is talking about this on another thread. I use the store brand ( HyVee) paper. I've noticed stuff sticks more to it these days than before but didn't know why. Not to worried, it's one- time use and if it peels off in shreds I don't care. It still comes off. Now if it got through and stuck the plans.....
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Here we've got it mostly together and drying. When I can lift it I need to sheet the bottom center section and put tip blocks on. The geodetic construction gives the stab a bunch of torsional rigidity to resist warps and twisting in flight. The first three Desperados had built- up and fully sheeted surfaces here. They are larger units so I was getting 4 ounce assemblies when finished. To cut weight here I went open bay stabilizer and solid, very light 3/8" elevators and trimmed out nearly two ounces. I was actually shocked how heavy those tails were. I'm not actually trying to build feather light with this design but THAT weight was in a bad and worthless place. Still had to be stiff tho. Twisty tails or rear fuselages are bad news.
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One last look inside. You can see the overflow way in there running up to the top front corner to get max fill with the airplane sitting normally on the ground.
No baffles? How does the thing do at the end of the engine run?
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Hi Tim. For me, baffles went out with bell bottoms. Never saw a benefit. In fact my last experience with them made me think it was blocking fuel entry. The run is very solid up to the last lap or two with a short speed up and cut off. Seldom ever a burp. There sure are a bunch of other tanks out there and no baffles. Also these planes are moving right along with a pretty consistent centrifugal force on the fuel. Baffles were more common with the old Fox where the airplanes seemed to almost stop in the air at times like the crowns of wing overs and overhead eights. Here the fuel might fall away from the feed line for a microsecond creating a burp or worse. The baffle in theory would hold a little fuel in the pocket.
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Stab is dry and ready to complete. I'm showing the shaping lines I've drawn on the edges. It's too easy to mis-shape these edges causing flying trim issues. Guide lines for carving and sanding are a little more accurate.
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For cutting hinge slits (not slots, I don't remove any material) I've made a simple wooden guide to center the slits and make cuts. Though this spreads the wood slightly a sanding block fixes the issue latter. I have a small assortment of these guides for different thicknesses of wood. Somebody should make and market sets of these.
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Remember these? I need to finish up a tail horn so it can be buried in the elevators soon. These were brazed from 1/8" music wire and Dubro steel straps I reworked a little including installing a brass bushing for the pushrod. I then plastered this up with some JB to keep the bushing in and fill pre drilled hole in the strap I don't need.
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I bent the arms as I needed in the wire bender and tweaked them up for alignment.
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Finally blew on a little chrome paint for rust proofing and its ready to be installed.
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You have as much scrap granite hanging around as I do. You in the countertop business?
Derek
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Derek not me personally. My employer ( the big orange box) does. My specialty is home appliances. Think of me when you grab your next cold one or wash your socks. Once in a while they change out the granite samples......
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Working on the elevators; blocked up while still square for drill horn holes.
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Marked showing slots for horn wire.
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Groovin'.....on a Tuesday afternoon.....
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A trial fit before shaping the elevators.
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Though I don't always do it this way, I'm glueing on plywood strips 1/32x3/32" to the trailing edges. This gives something solid to sand to and will help withstand banging into doors frames and warpage.
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Oh, there he goes off the reservation again. Hinges shoved into the slits. Absolutely NO glue or epoxy. Drilled vertical holes through the hinges where tooth picks will be glued in to retain. Nothing in the hinges to bind them up. Pockets are for money not hinges. The airplane will be covered and finished with everything already joined. The hinges can self-align when worked a few times then the finishing dope will lock them from twisting. Dope doesn't stick to nylon. y1
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Good to go. 2.5 ounces with horn and hinges.
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No glue on my hinges either. Only CA on the toothpick to hold it in place.
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No glue on my hinges either. Only CA on the toothpick to hold it in place.
Yeah John I've done it that way as long as I can remember. The time or two I tried to glue them in the epoxy went where I didn't want it. Since I have the airplane all together from the first drop of dope it's very easy to pin the hinges. Where the trailing edge is a quarter square there is plenty of hinge sticking through the backside I'll glue those from the back or inside (wing trailing edge) and not weaken the 1/4 sq. by drilling it.
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The car is loaded and killing time till I head for Muncie in the AM. Sanded up the wing and put it on the scale. As shown complete with landing gear but no flaps 11.5 ounces. Not too bad. Not trying for an ultralight but when I can keep the weight down I have room for a little more finish.
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Good luck at the Nats, Dave.
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Good luck at the Nats, Dave.
Randy Thank You so much. Lots of work to do.
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Well Dave depending on when you finally got on the road, you are closer to the NATS than I will be. Just have a safe trip there and back. Don't forget to have fun and say hi to all the guys/gals.
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We will be getting back on this build real soon. I've got a couple things to whip up for some others real quick and after test flying the green Desperado this week with the Jett .76 I'm so taken with it that I'm converting the red one to .76 by just lengthening the pipe tunnel and the rest of the fleet is retired. After flying both engines back to back AND watching video tape for the first time of my flying it was immediately obvious how the .61 ships slow down on the tops of loops and consecutive intersections, affecting shape. The bad part is now I have to learn to fly again. The amazing part is the .76 isn't really using much more fuel so I'm still pulling fuel out of the 7 ounce tank. I can slow my laps a little and still get much better drive through maneuvers-win- win. The one we are building now I will try to cut weight enough that it should work much better with my .61's but can easily take the .76 from the start.
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The bigger, the better, when it comes to engines.
Marcus
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Well at least maybe I found it. (&$!??x). The red airplane now has the .76 and is truly now a point-and-shoot airplane, me likes a lot! This ship always flew superb, mostly better than the rest except for one bad flaw which kept it home for this Nats. Without fail the third turn in the hourglass I'd see the bottom of the airplane suddenly and it would head for green acres. Tried everything. Thought more power might solve it. Nope. Now remember my shpeel about ribs crushing with shrinkage? Once again. Can you see it in the photo? I think it's causing a tip stall at a bad time. So next project is to fix this by cutting the covering on the last bays and tips both sides and shoring up the ribs. This one could make the team trials so best get with it.
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What it looked like under the silk span.
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Wow,That looks ugly.A piece of 1/16 x 1/8 or even 1/4 with the grain going the other way will fix it.I always thought that was a weak point in almost all built up wings.I wonder if building up the ribs like a full size aircraft would be worth the extra effort.It would eliminate that problem and might be lighter to boot.Trax
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Hi Jeff! For me this issue began with this v- tip in that before I usually had some hollow block or thick sheet tip which supported the airfoil at the tip rib. With this design that last rib is rather unsupported and needs to be beefed. I have a fair amount of finish here which may be causing a little more shrink, even with the non- tautening Certified. The fix this time is to replace the lightened 1/16" ribs with mostly solid 3/32" and a little webbing between the spars. Since this is the third one I've had this issue with I'm going back to the new one I'm building to beef it up and changing my drawings likewise. My theory is the solid thicker ribs will do the job without adding much weight or extra work. Hope you got a new project on the table. It's only about 49 weeks until the 2014 Nats fella!
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Dave,For the short term I am whipping up a simple Fuselage for my SV22 wing and tail.Dayton is next week,Detroit the week after,FCM next.I definately want a good flying ship by the team trials.While I'm helping out I am going to input as much stunt info as I can and try not to explode LL~ LL~ Oh Yea,I wanna do a bunch of flyin' too.I have most of the components framed up for my Shark 45.That is my main project for building season.I'm really going to try for a nice finish.Don't know if I'll ever get one of those Concourse trophies but I don't want to be in the back row with brother Dan's Vista again next year!!Trax
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Boy this is terribly slow right now. After the TTs next week it will start rolling again. I started getting the fuse together. Here I'm using epoxy to assemble the front end. The mounts and spacer block were made as an assembly down on the flat granite to ensure the mounts are flat and square. Team racers Jim Dunkin and Bill Wright drilled this into me years ago. A hot engine case can be warped if screwed down unevenly. Then I drilled the mounting holes and lightening holes on the drill press. I use 1/2" sq. mounts because the nose is short and I need the fuselage width to get enough fuel tank in. Then I've put temporary pins through the fuse to lay and position the mounts correctly. These are pulled later.
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Good luck at the team trials Dave.
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Yes, Dave, Good Luck at the Team Trials!
BIG Bear
RNMM/AMM
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Thank you guys. We'll sure have a good time. I'm not happy with how little flying time I've gotten since the Nats but I'm sure liking the .76. I'm going to dedicate a major effort to find a new place to fly. Getting tired of fighting the soccer bunch and schools around who choose the park for gym class instead of the school grounds. Must be something better.
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Hey Dave I too have been looking around for places to fly as the circle at Shawnee Mission Park is too small with that hedge tree on the back side. Can't wander hardly three feet. Don't ask me how I know. Have looked at the ball diamonds down in the park. Don't see any lights and the one ball field is away from the road. Have also never seen the ball diamonds being used. May try it out after the Topeka contest. Haven't flown since Memorial Day weekend.
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Let me know. There are a couple industrial parks down my way and a big sports park out south where my daughter's new house is I'm going to check out. Tempted to Google maps the area and try to spot some places. If need be we'll restart the old club for creds. (You pick which club: Sky Devils, Sodbusters, Super Tigers, Knights......)Four clubs at one time. Now us and no place to fly.......see you in the morning John.
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On the way home from my granddaughters birthday party, I passed the sign, Fleming Park this way. It is the KCRC flying field in which some of the guys are now coming around to CL activity after the fun flies that have been held there. It is an area marked for CL and helicopters. There is a pave square big enough to make decent take offs and the rest is grass. Yes it requires a permit to fly there unless there is a special sanctioned contest. The Minors just had a F2D meet there. Great turn out and a lot of combat. saw Jim Piscetto there that weekend mowing the grass the KCRC group has to maintain. I guess you have to be a member of the KCRC to get a park permit and also an AMA license. Thought of that for 2014 with one day set aside during the week for flying. Of course Sat and Sun would share with the rotor wing group. Now I am in full retirement I wouldn't mind driving out there to fly. Also no keys needed to get access is my big draw to the site as well as the safety of a fence. I know that there are more than just the two of us. Problem is getting all the KC area CL people together. This could become another Buder Park on a small scale. H^^
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Just wanted to add a note. I'm putting this particular build on the shelf for now. Having flown the TTs and working some with my new (for me) .76/.75 power packages I really think the standard Desperado is just a little too small for it. It's very hard to keep this and a credible finish on 650 sq.s and still keep the wing loading within competitive limits. So I'm starting a pair of new 105% Desperado. When I get the wings built and up to the same building stage we were on here I'll pick up from where we left off. The new version pushes the area up to about 700 squares which I believe is better for this design, power, and weight. Frankly the rather still air this time in Muncie showed me I didn't allow every situation. I built for wind and it didn't happen. That's why we keep trying I guess.
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Well, the StarGazer isn't very big. Neither is Jim Aron's hot rod and both use big blocks.
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Dave, I agree with Randy - I'm running my PA75 in a Trivial Pursuit based airframe and it's just a wonderful combo! Finish this one and "big block" it!
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Yes I sure know that and in fact Uncle Jimby's airplane got me interested in going smaller. Perhaps it's airfoil but more likely just weight. Jim's airplane was 65 ounces last I knew. David's is in the same ball park. My last three were 70-75. The first three of these I built flew wonderfully at 61-63 ounces but were covered in jap and almost no finish. This later bunch I put on a Nats worthy finish and made one take-apart. I also have to fly off a soccer field with washboard landings and an occasional flip over so the airplane and landing gear are a lot more robust than a pavement airplane so more wood more epoxy ..... I wish I could build a hollow shell airplane but it would be splinters on my flying site so I just think I need to go a little larger with more area. I'm still going to try backing off on the finish a little but am going to have to chew at this a little from both ends. I find the Certified dope a great product but much more dense in filler and weight. I'm going to thin it much more and sand it better. Might go back to jap tissue too. Everything is compromise. If I were sticking with the wonderful .61s I have I would stay with the standard airplane but I seem to have endless power with the big blocks so I can afford more size with the plane. I could circle back in out years but going to try this path. Yesterday I took out my old Only Vegas airplane with a .76 in it for the first time. It's 716 squares and was super with the newfound power. I left those behind for smaller ships when I found the power limits of the .61. Those limits are gone with these truck motors!
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Worked on control horns this morning. The photo shows horns in various stages. The flap brazements, the Delrin uprights and then riveted on. The very top are elevator horn brazements with a brass bushing installed. You'll notice I'm not much on slidy/adjusty/faily stuff. Most of these type adjustments can be made other ways without risking trouble.
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Here the flap horns are finished at the top. The elevator horns are ready to bend and shoot with chrome enamel to prevent rust. I JB'ed the brass bushings in after the brazing was done to ensure they stay put. I flew one for years where the bushing had fallen out. More than enough slop in the controls but it flew very well and when finally salvaged didn't really find any extra wear. That area doesn't get near the abuse the flap horn does. That's why it's so much more heavy duty. I have at times put various bushings on before bending the wire ends but now simply use plywood traps glued to the fuse sides on the inside after assembly. This is a good place to shore up the fuse anyway so they serve multi purpose. With pipe ships you don't have any oil ingress in this area so the plywood holds up well. On a muffled or open exhaust airplane like classic I'd more likely slip wheel collars on the wire, then epoxy those to the fuse sides inside.
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OK the winter building season control hardware supply is ready to go.
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Have cut ribs and ready to start the new 105% Desperado wings. Took this day to re-connect with the fam and took my granddaughter to the zoo. It gave me a chance to reflect on the season which, for me was kind of a bear...
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And I feel a little like I'm in the stunt desert....
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But I got thinking about the coming Aussie world champs and decided to get back to the shop and work on new creations- like I found these guys today, on the left....
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So lets get swimming....
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Steady progress. The pair of new wings nearing completion. They are rougly 3/4" longer and wider in chord. To stiffen then some a pulled the trailing edge sheet further forward to a full 3" and added 1/8 sq. spars to support it. At this stage the first one with landing gear installed is 11.3 ounces.
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Re-thinking the .60 pipe setup.......
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Splended idea Dave.You could call it Downtown Brown LL~ LL~ LL~ LL~
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That looks like the famous Metkemeijer .77 engine. Where did you get one? L
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Lauri it's a Brown Junior C made in April 1937. I'm actually going to build a 1939 Tiger Shark G-line like in the AMA museum for it and fly it for fun/demo, although I'll put a two line system in instead of flying it from a fishing pole. That Brown is too valuable to risk screwing up.
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LL~ LL~ LL~
Nice engine!!!
Marcus
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Oh, should've looked more carefully. I can now see some differences. L
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What's old is new again! Interesting setup Lauri!
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An update to say we'll be getting back on this within a couple weeks. I got sidetracked. I've been at the new flying field when I can be and getting a new club started, Sky Kings of the Ring, KC Chapter. Thinking to make this a larger regional club with local chapters. There are many lonesome island flyers out in the Burgs and Villes who might like to join a club. With the net it's now possible. A chartered club must have at least 5 members. This way the lone flyer can enjoy club benefits including insurance for flying site owners. Working......anyway.... Built two of these Flying Clowns with Enya .19s for club trainers and decided to build myself a new Sukhoi profile for winter flying here. KC winter flying consists of a couple flights every two weeks during a rare 46-50 degree warm afternoon. It might be muddy, wet or icy so messing with the pipes and carbon props in the brittle cold for a couple quick flight doesn't appeal. My Sukhoi with a Enya ss .40 will be the alternative to not flying at all. Should be flying this by next week so back on the Desperados. Bob Brookins in Des Moines reports his Desperado is coming along. His is getting the PA .65.
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Sukhoi..
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Getting close. Covered the Sukhoi today. In the photo the wings are still wet. This is a study in different covering for different reasons. You can see the carbon for the fuselage to make it stiff. The flaps and elevators are covered with light silkspan to cover grain. Jap Tissue on the stabilizer for light weight and very little shrinkage to prevent warps and Plyspan on the wings for toughness given all open bays. It will get one coat of Certified tautening clear then non-tautening thereafter. Hope to fly it next week and clear the bench.
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Looking good. May be a little muddy out at the new circle tho.
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With dope drying on the Sukhoi I got the Desperados up on the table tonight for the first time in a while. I made wing tips and mounted my reference blocks as shown on the wing using the incidence meter to get them parallel with the wing centerline. These will be the major point of measure to get all other components aligned and the controls set up. Only when I'm ready to cover the wings will I cut it away.
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Tonight I got SU-26 done and ready for winter practice. Didn't do much on detail with it since this will be a work horse not a show horse. Now I can get back to the keeping the main thing the main thing. Hope I get the chance to fly this in the next week. I'm sensing it a little nose heavy but we'll see.
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Looks great in the pictures and I know it will look better in person. Let me know when. just have to remember to pick up grandkids from school.
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Getting going again. I decided to go back to the built up sheet covered flaps I used for years. I had been using 1/4" sheet with carbon which are tortionally stiff enough but wouldn't stay straight over time. The first Desperado has had at least one flap changed out three different times. I don't remember having many of these problems with the built up flaps. I'm also trying something new. The outer 5" of each flap will be a separate section which are joined with a 1/16" wire joiner and can be 'tweaked' independently from the rest of the flap, but moves right along with the flap and aren't stationary trim tabs.
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Here you can see I'm making that modification to one of the existing Desperados.
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Cool "tip" Dave... 8)
Marcus
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Boy this business about earning a living is sure getting in the way of my building time. Should be outlawed. Tonight I'm sheeting the wing flaps. The 1/16 sheet was glued to the flap core leading edges yesterday and blocked flat to dry. Now I spread the sheets to run cement down the ribs and along the trailing edges.
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Now pinning them down on the board with a shim to get the trailing edge in line with the leading edge. I've long wanted to build a holding fixture for this operation but have yet to do it.
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With the inner flap sections mostly complete I have tack glued the outer flap sections which are solid 3/8" on and have drilled/relieved the leading edge to insert the 1/16" music wire joiners with epoxy. Once set I can sand the outer sections to match the inner and then cut them apart other than the joiner. For today after I glue these they will be set aside and I'll built the stabs and elevators.
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The second stab framed up. Just needs center sheet and shaping.
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A little trick I use sometimes. The outer flap sections need to be shaped down to match the inner sections. So that I get a consistent thickness at the trailing edge I cut 1/8" strips of 1/32" plywood and tack glued them on the trailing edge of both. Now I can sand to the plywood and not go too far. When done the plywood strips are removed and a perfect edge remains.
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The next steps are where I go seriously politically incorrect. You will see me dare to join the flaps, hinge them to the wing before its in the fuselage and before the airplane is covered and and finished. Then you will watch me commit the extreme dastardly act of connecting the controls solidly with no adjustable gizmos.
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Today we've joined the flaps and elevators with control horns.
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I'm cutting slits in the stab and elevators for hinges. Here is one of those fixtures I made to cut straight and centered.
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After inserting each hinge in the stab we drill a 5/64 hole through to receive a toothpick pin.
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Half a toothpick is shoved in after a shot of Gorilla glue. After they set the toothpicks are trimmed off with big toenail clippers and sanded flat. Nothing more is required to hold the hinges in.
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The elevators are joined on, pins installed and a little final shaping done. Ready for binnus.
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Tail of the tape (tale of the tail?)
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Hinging of the flaps. Since the hinges protrude through the back of the 1/4 sq. trailing edge and the glue holes show I am glueing them from the backside and not pinning these. I WILL pin the other end into the flaps.
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The pushrod is retained with a wheel collar. These will get a little JB Weld as well before they are sealed up in the fuselage.
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On the scale. With landing gear and flaps I get 16 oz. each. Wish they were less but it is what it is. They are pretty big and need to be pretty solid for me on the grass field.
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The wings are ready.
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Chopping out fuse sides.
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Looking good Dave, now when is the weather going to co-operate so we can fly?
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Sure don't know Doc. Charlie Reeves is supposed to come visit and bring airplanes to fly over Thanksgiving. Haven't heard from him recently but I hope the weather cooperates. I got a couple flights last week. You may have to meet up with him depending on my crazy work schedule.
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That pin method for the hinges is very interesting! I may have to try that out on a future plane.
It's looking good so far Dave! Makes me miss the shop at home and messing around with balsa and building planes.
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Matt it never gets old. I have to kick myself out of the shop to go flying when I can. Never enough time.
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Tonight I finished cutting the sides and 1/16" plywood doublers. Some don't use ply doublers here but I still believe in them. I don't want the .76's torquing the nose off or bouncing off on the rough grass rollouts.
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Will epoxy the sides on and call it a night.
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Tonight I finished cutting the sides and 1/16" plywood doublers. Some don't use ply doublers here but I still believe in them. I don't want the .76's torquing the nose off or bouncing off on the rough grass rollouts.
For what it's worth, my grandfather sees the nose twist on my Trivial Pursuit with a 76 RO-Jett in it when I start it up. That's with 1/32" ply doublers. Probably would be best to go with 1/16" in the future with that motor
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Side doublers on and weighted with granite slabs to flatten.
Matt the Jett .76 is sure a potent twister. The force even to start it over the .61 is quite noticeable. I'm going to back way off on the use of carbon to save weight but I will still put the .5 carbon on the nose back to the wing high point for stiffness.
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Not much tonight but here I'm making the motor mount assemblies down flat on the granite. I'm using 1/2" sq. motor mounts. Don McClave gave me that look when I was lifting, er, buying the mounts from Tom Morris at the Nats. He told me the 3/8x1/2 were adequate. I thanked him and told him my airplane has a short nose and I needed the wide mounts for fuel tank capacity. Not sure he bought it but.... I'll lighten them later by drilling holes down the backside.
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Here are sides where I glued up the doublers yesterday.
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Lastly for tonight I pulled the Enya ss.40 off the Sukhoi and am putting that new FP on. Not super thrilled so far with that Enya. I'll work with it but don't have time now. I know I can make the FP work for me chop chop! The Enya still seems too tight after two hours run time. Also vibrated more than I liked. That might have been that big spinner I had on it but I'm on to other things for now.
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A few frames tonight....I cut plywood bulkheads for behind the fuel tank compartment and epoxied them in position.
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I've drilled accurate holes through the fuselage sides to receive 1/16 music wire pins which will help locate the motor mount block. Epoxy is applied and the motor block is inserted between the sides and made to rest on the wire pins. This assembly is blocked and clamped in square alignment and allowed to cure.
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In the morning after the epoxy is really solid I'll twist the pins out and start cutting the rest of the bulkheads. If it all goes well we'll have two completed fuselage boxes but tomorrow evening.
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Bulkheads drawn out on 3/32 soft wood.
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Any method to get a straight fuselage is a good one. I have drawn a center line down on the work surface and centerlines on all bulkheads. I am blocking, pinning and whatever it takes to get the sides in the right position.
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We've got the bulkheads in. I use webbing between sides and bulkheads to eliminate fuselage twisting. I'll put in a little of that to help hold things in shape until final assembly but can't do it all as long as we still need to glue inside joints and hook up the controls.
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In the process of pinning the bulkheads in I cracked a couple of them along the grain so I put a cross- grain doubler on each to give them a little more stability across the fuse. A heavy handed pit man could crush these while launching.
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Well see if I pick up your plane again. I know I'm club fisted. LL~ LL~ LL~ I do the cross piece of balsa on all formers made of vertical grain balsa. Started cutting riblets for my next project yesterday. This exercising is getting me. But, hope to get in better shape. H^^
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What? More flaps? Well this is just about exactly the point where I left off with the regular size Desperado set aside to build the larger ones. I've decided to pull it right along with the other two. Finishing three airplanes at once will be a challenge but there is some chance I may have to give up my workshop space for a while in a couple months so ....
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It's time to join the wings with a fuselage. Since I choose to put my landing gear permanently in the wing as well as mount the flaps, the bottom of fuse gets cut. Wish I didn't need to do that but it's the least of the evils and goes right back nicely with doublers inside.
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The wing is blocked up perfectly level using the alignment block and incidence meter.
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The fuselage is put on and then I go through whatever contortions are required to get it aligned in the horizontal plain, perpendicular to the wing trailing edge. When I've got that pinned in place I then put the incidence meter on the motor mount block to get it in line with the wing centerline, shimming as required.
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Well, I like it! Dabs of epoxy inside to lock it in.
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Really slow... A little better work schedule next week so maybe we'll make more progress. The wings are in the two big birds and now I need to put the bottom cut outs back. Somehow I always have to trim these a little to fit right. The wing always seem to be about 1/16" thicker than the drawings allow for. I tack glue some scraps as alignment tabs on the pieces.
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These are glued with a light dab of epoxy.
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You can see the balsa patterns I made for cutting 1/16" plywood doublers. Didn't mention I traced these off the side earlier before putting the wing in. The doublers are epoxied and clamped to cure. Tomorrow I'll glue inside all around the wing continuous and start getting the small ship caught up to this point. Need to finish the flaps and get them mounted on the wing. The fuse is ready to fit the wing.
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Very nice Dave!!!!
Marcus
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Thanks Marcus. Looks like the weather might give me chance to get a few flights today- hooray!!!!
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Moments ago... Straining at the leash.... The FP.40.... Three patterns in so far.... Better N home grown maters!
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FP at 8700 rpm, 11-5 APC, 60' lines, about 5.3 laps, 3.5 ounces fuel for 7 min.
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Six in and need to call it a day. The forecast tells me it might not break 40 degrees for the next six weeks. The FP seems to like my classic fuel 10/29 a little better than my pipe fuel 15/23.
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I knew I should have come by the field. Was on the way home from theropy and thought about driving by. Still had the planes in the old Ford. Need to see the plane in person.
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John I wish you did. Last great weather day for a while I guess, but I'm ready in case.
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Go Sukhoi at the Aussie Nats Mr. Batty!!!!
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Thought this was interesting. Here I have the regular Desperado wing on the right with the new 105% version on the left. You can see the difference. The weight difference between the two wings with landing gear, flaps etc., is two ounces. Doesn't sound like much given the size difference.
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Got the wing in the smaller plane. I'm using 1/4" plywood 'bearings' for the flap horns, epoxied to the fuse sides. Takes the strain off the hinges and greatly extends the life of the airplane.
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This evening we are mounting the stabilizers. First I fit the rear section of pushrod with a wheel collar.
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I do the rear pushrods (3/32" mw) in two parts which are soldered together, the only solder joint in the whole system. This allows me to set perfect level on both flaps and elevator, then solder the pushrods.
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I'm setting the stab square three ways. Here I've made a tool to get both stab tips at the hinge line equadistant from the flap hinge line. When it there it's pinned so as not to move.
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Now I'm going back to my level reference block to get the airplane set level.
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The incidence meter is set on the stab so I can adjust it to 0-0 degrees. I know some are using a little positive incidence here. I'm not quite there with that yet.
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Now I'm trusting my calibrated eyeballs to get the stab parallel with the wing in this rear view.
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After messing with that I want to check this once more then mix a little 5 minute epoxy to spot on a couple places on the outside where the stab and fuse meet underneath. This is very lightly done. After I finish the fuselage it's possible there might be a little twist and I like to be able the crack it loose and reset if need be the get it straight. This is absolutely critical!
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While in my waking stupor before coffee this morning I had a revelation about a new look for the airplane. Think I'll keep the 105s the same but give the new look and maybe a new name to the regular sized ship. Going to be really pushing to get these done ASAP. Have a daughter and grandson moving back home from Florida in Feb or March and have to give up the workspace for a while. Think I can keep a work table and the scroll saw up in my bedroom but larger projects will have to wait. Maybe I'll do some smaller old time stuff I've got on the back burner. Life evolves.
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The goal for today is to get the controls hooked up on all three airplanes. I first get the ship leveled going back again to the level reference block.
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Now I put the beam back on the meter and span the wing and the flaps looking to get this level.
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Here you see the balsa block used to hold the flaps in place once level is achieved.
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The elevators are locked in neutral position.
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These are pushrod fair leads made up from 1/16" plywood. I'll use two on each airplane- one fore and one aft of the pushrod joint.
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These will dangle on the 3/32" music wire pushrod until after everything is connected, then glued to the bulkhead. This prevents pushrod flex.
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Here the pushrods are being wrapped with fine brass wire. This will be soldered with resin core.
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Here the forward end is retained with a wheel collar. These will get some JB weld to prevent vibration from loosening them down the road.
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Tonight I did the epoxy all around the wing to fuselage joint inside. I prefer to get no epoxy outside because dope doesn't stick very well to it and will blister pretty easy off it. I am looking at the soon-to- be pipe area.
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'Exit ramp'
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Now soft 3/32" floor.
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Everything looks great Dave but I can't help but wonder, is there any special reason you're still using "old school" spliced pushrods?
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Dave you don't know me real well but I want to make a constructive criticism on your push rods system. The way you are doing it is NOT the best way. Three reasons, first is flex and second is the chance for slippage and lastly is weight. That weighs about twice as much as a CF pushrod and is not as strong and is not as reliable. Just a thought for your next plane.
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Hi guys. Maybe it's just an old dog thing. I used a couple CF rods way back. They were OK but I had to use quick links on them to get fine adjustments. When people started losing airplanes over quick links I stopped using them. I know they weigh a little less but I'm not too fanatical about it. I like the ability to nail the level adjustment more. I suppose I could fiddle with carbon rod and get the length perfect but seems more time consuming than i think worth it . As far as flex, they will if not supported but there I'm using plywood fair leads which control that. The first use i remember seeing of the carbon rod was the Impact and Blue Max take apart airplanes where the wing came out and the pushrod had to swing down to remove. It required no pushrod support to allow the movement so carbon was the answer. I dont think it was about weight then. That was just a bonus. By the time I would be happy with it, it may not weigh less anyway. Maybe it's because I've done this reliably for so long I can seal it up in the fuselage and forget about it. It won't let me down. Maybe it's the Ford/Chevy thing- I drive Pontiac. Robert your new ship is looking really great! Can't wait to see it this summer.
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I too still do the two piece push rod thing. But do you really save that much weight with carbon rods? By the time you add the ball links, which I am thoroughly sold on and wrap the carbon at the end so it doesn't split, yes I've had the ends split, is it lighter? Guess I will have to grab the old scale and check for myself. On my latest project I weighed the new leading edge and compared to the original leading edge of the plane. A full 2 ounces of difference. Pictures forth coming.
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John I'm not sure. I'd graft in 3/32 wire to tie on to. I'm going to risk saying that this was a follow the leader thing with many doing this without really understanding why or what brought it on in the first place. There are a few other things like that in this here sport!
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John I'm not sure. I'd graft in 3/32 wire to tie on to. I'm going to risk saying that this was a follow the leader thing with many doing this without really understanding why or what brought it on in the first place. There are a few other things like that in this here sport!
Roger that brother Dave! Sometimes change is for the better, sometimes change is just....change. Doing it just cuz the other guy is doing it ain't a good enough reason!
BTW have been admiring your build all along the way - keep posting the lessons!
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Hey Denny!!! Yaw mon!
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To each his own Dave, I will agree that quick links aren't the greatest thing.
I'm also an "if it ain't broke don't fix it" kinda guy, but FWIW...
I've never had a quick link fail on me, but a half dozen or so models ago I started using ball links exclusively and have found them to be a LOT better. I use Du-Bro 4-40's and also add a jam nut at the end of the link. I use JB Weld to install the threaded fittings into the carbon tube, no wrapping. Properly set up you'll have perfectly smooth operation, and no slop anywhere. I'd say it's splitting hairs on the overall weight difference, and it's not difficult at all to nail the proper length. I usually build mine starting out with the ball links threaded midway or slightly more onto the fittings, and then cut the carbon pushrod to the necessary length. Done right, this leaves enough adjustment for absolute fine tuning. With the control arms, all you have to do with them is tap the holes for the ball link connection. It's totally the way to go Dave, try it, you'll like it. y1
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Mornin' Wayne. I know the ball links have caught on. I'm sure they are fine and you can get adjustment with them. They are probably strong enough. I doubt I'll be using them until I find a reason they improve my game. ( I sensed you rolling your eyes). OK here's my beef with them. The very thing many tout as a virtue with them, no slop or play in the controls is exactly my problem with them. I don't like the feel of tight controls and they don't allow for any slight misalignment or anomaly in a flying surface. These then REQUIRE the ability to fine tinker the adjustments to set right where my antiquated method is more tolerant and I'm not fiddling with it. This I think is more a personal preference and I call it just that. There sure was a big push toward these by a few which is fine but I would struggle with any idea that they are required to be competitive as some might assert.
Been slow about getting those drawings to you. I need to doctor them some but haven't had the bench clear to do it. I'll get it together eventually Wayne.
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Like Dave, I prefer slop in the control system as well. LOADS OF IT!!!!!!!!
That being said I use a combination of ball links and clevises throughout the system. I use the ball link at the BC where the short rod attaches to the BC. That way there is no bind with an L bend. And UHP clevises all the way back from there on Carbon rods both front and back. At the elevator horn I hog out the hole some where the clevis goes through and that gives me my elevator slop. I usually start with a 1/16" amount and it goes up from there as the system wears in. For some reason that slop loose feel in the system gives me more ability to finesse it, read that fudge it when I blow it, around the bottoms and nail my angles.
The rods are the small central hobbies ones with the titanium 4/40 fittings. Not the big fat arrow shafts. With the carbon rods you have no need for guides and you can take out most of the formers in your model before you close it up. Since you have a pipe floor and the top of the fuse sides are filled with cross grain balsa (very nice I might add!) you could go back and take out most of the former used in the initial layup leaving just a small window frame look at each former. You have a box with the top and bottom closed and that box fuse is really strong. With no plywood guides and the extra former material out of there that is where the weight savings comes in and you have not sacrificed any strength in the controls.
At the same time what you are using works and you like it so no need to change it. I just wanted to say there is a way to get slop with ball links. And no I would never use a quick link...
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By the way. I have checked this thread every day since day one. I think your plane looks great and I cant wait to see the rest of it and the finish. Thank you for taking the time to post pics and how you go about the builds. There is always so much I learn from these build threads!
Thanks again.
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I like this thread a lot. And it's nice tosee different approaches to various things...
About the slop, many years ago the GT Bicycles freestyle team came for a series of shows here.
I was hired to be the TM, as I already knew some of them.
One of the riders, Brian Blyther, one of heroes, came on this trip, and while we were having a little fun, I picked his bike to play around...
There was nothing "tight", everything was loose.. I couldn't really ride his bike.
Later, I asked another guy from the team if that was really the way Brian rode his bike, and Dave answered with no words, just a crazy face... n~
I must have my controls slop free, but that's me...
Anyway, I think the carbon pushrod could be a cool improvement.
Marcus
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Doug and Marcus. Thank you very much. Sometimes I've wondered if anybody is following along. And Doug I still lay claim to 'King of Slop'. I remember reading in years past how others had to go back in and loosen controls up. I recall Bill Werwage telling how after he rebuilt the controls in one it didn't fly right and had to go back in and slop them up some to cure hunting. That can drive a sane man over the edge, especially if its fine upright but hunts inverted etc. I am glad we can all do stuff our own way because like Marcus said, it can feel very different to the individual. After 50 years this dog barks like he learned it as a pup.
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I'm watching too - always learning. These threads always draw interesting, informative comments too.
SK
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Glad you are on board Serge. Tonight I'm putting the rest of the 1/16 sheet fuse webbing top and bottom. Also putting in the tail gear wire. The first shot is a 1/16 plywood platform and 1/16 music wire gear.
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I tack glue the wire in place to make wrapping easy. Also you can see I have a .027 lead out cable looping through. This is my stooge launching cable. I also hang the airplane from this cable at home. I think it's the best way to keep the airplane straight in storage.
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I won't be winning any sewing bee but I sew soft brass wire to lash the gear and cable to the plywood.
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Here I glue on some 1/8sq. to gain some glue contact surface.
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Now epoxy is applied over all wraps then inserted in the fuselage. The blue tape keeps epoxy off where I don't need it.
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Tape pulled, job done. Next airplane.
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I too am watching! As a matter of fact I stole your wing tip idea for my last plane, amazingly light, and easy to do:)
It's a bit of a trick to get an adjustable leadout in them, but nothing too hard:)
Keep going! I'm learning!
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This I think is more a personal preference and I call it just that.
No problem Dave just tossing it out there, personal preference is all that really matters.
No sweat on the drawings either Dave, I definitely want to get ahold of them, but whenever you have the extra time. H^^
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Hey Dave, the old DOC is here watching your progress. I am glad that Mother and Grandma taught us boys how to sew tears on shirts and pants. Also learned how to do buttons. When I seen your post about the daughter and grandson, I was wishing I had built the shop I wanted. There would have been enough room in one corner for ya.
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Oh John thank you. That got accelerated. They arrived last night. Going to try to make do here long enough to get these planes finished up then shut 'er down and make living quarters out of it. Hoping I can finish these in maybe four weeks or less. I can rub them out on the bed. Maybe this youngest grandson will take to the hobby. Got to teach him to walk and talk first! Probably put him in the jumper seat next to grandpa today and watch me cut balsa. Junior Nats Champ in the making. These ships might be pretty light. Don't know how much finish I'll have time to do. Bet the dope smell ...........
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This will make two champs in the works. Just need to get the one out more often. I have planes that need a pilot.
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Yeah Dylan likes to fly but gets bored in the shop. Have to see about baby Bryce. Maybe their girl cousin will show them up. One thing for sure. Grandpa has enough stuff to keep them going as long as they have interest. I bought about 40 engines this year, .049s , .15s, .19s, .29s, and .35s , to supply them. Now just have to see which of them will jump in.
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What the? Here's where I am starting the modifications I talked about on the regular sized plane. I remember seeing some old 1930s-40s fictitious serial aviation character drawings or cartoons for Capt. Eddie and his super fighter. Think that. You are in 1935. What would a futuristic fighter look like given what you knew then.
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That sure is different.
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Cap'n Eddie checking out his new ride.
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By Tom of Finland?
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Lauri, by Slimline of Arizona. (Made in China)
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The Duke, Gramps and Dick awaiting their machines.
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I need some 3/4" 4-6 lb. blocks for top blocks but we can no longer buy 4-6 lb. thicker than 3/8". If you can pick and choose you could find light block. Since most of us have to mail order light wood the option is to laminate thinner planks to get thick blocks.
The picture shows mixed 15 minute epoxy poured on the wood. Then I use an old plastic gift card to spread it around then scrape it off to near dry. Then the wood is mated and weighted flat. I have used cement for this but you need to leave it wet. It leaves a float between layers and when you carve the block even days later you find wet cement because it didn't get air to dry. You then have to stop to let that glue dry then carve a little more. Epoxy will cure but you have to get that extra weight scraped off.
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A run down on what we got done today. Working mostly on the Capt. Eddie airplane I needed to start getting the front together to set the top block to do the rear deck sheeting to.......... Something I know unusual or peculiar to my airplanes is a 1/4" balsa fill just over the motor mounts. This goes back to Music. Simply, I like to keep the engine centerline within 3/4" of the wing centerline for more even inside/outside turns and maybe a little closer on vertical CG. With a thicker wing and the mounts at the top of the fuselage sides there isn't much meat in sides and doublers passing over the top of the wing-hardly any. So the sides are raised 1/4" at the first bulkhead to get more strength against vibration and torsion. I then use the 1/4" balsa fill block forward which also makes shaping the nose easier.
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Now I am building in blocks around the nose to mount the plywood nose ring.
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Bolting in the RO Jett .61 and twisting in a little engine offset.
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With the engine in I can now use it to perfectly position the 1/8" plywood nose ring. I use 1/8 because the ring is integral to holding the cowling on as you will see. I have an old 2" spinner backplate that has become a tool for this operation. I use a lot of double sided tape as I build and here pieces are placed on the backplate and then card stock spacer shims are stuck on. Then the 1/8 ply ring is stuck to that.
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I test fit and build wood out or sand it back to get a light contact to the ring.
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To help with this I have sandpaper stuck to the back of a larger back plate which I can use to sand it in. Jim Lee makes a great tool for this.
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When ready I mark where epoxy needs to be applied.
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Then the ring and backplate is shoved on and tightened up.
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When cured the engine is pulled and the ring remains.
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Looking at the weather. Light snow tomorrow on the L-Pad but back here in KC 49, sun and light wind. Might go get a couple flights in tomorrow afternoon!!
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Dave, you need to try the Gorilla Glue sometime for laminations. Have not weighed it but I think it is lighter and stronger than Epoxy. It also sands very easily. Just spotted my Music kit that I had pulled off the shelf some time ago. Have never started it. guess after the current stuff may have to start it for my RO-Jet .40 BSRE with the mini muffler.
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Dave, you need to try the Gorilla Glue sometime for laminations. Have not weighed it but I think it is lighter and stronger than Epoxy. It also sands very easily. Just spotted my Music kit that I had pulled off the shelf some time ago. Have never started it. guess after the current stuff may have to start it for my RO-Jet .40 BSRE with the mini muffler.
Yup!
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Won't be much new to see tonight. I rough cut the top block and tack-glued it on with cement. Tomorrow I'll start making the big mess and begin carving. Some are making mold bucks and molding these areas from 3/32 sheet and the like. Really nice! I don't make too many exact copies so can't see the investment in time for a one or two shot deal. Weigh less? Really not sure and can't be much. That depends on how thin you hollow the block. My mind says a block hollowed to 3/32 or molding 3/32 sheet should weight the same sans normal wood variations. If its that thin you'll still need some former support to hold shape long term. Set, game, match. However if I knew I were going to produce at least 6-10 like copies I'd probably do so. Here it's done and I'm on to other things while another is still sanding that mold buck.
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Nice going Dave. 8)
Marcus
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Thank you Marcus. Got all the top blocks tacked on ready to carve and all three noses together. Lastly I cut and lightened the bottom blocks then glued them on permanently. Here is the smaller ship which should use the .61 but I fitted the pipe tunnel to take a .76 should I decide later to put that in. Flexibility. It's shop night at Pop's so clearing the table so Kevin can work on his Ruffy.
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Kevin doing his first cloth hinge job.
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This morning I've been working the top blocks to shape. Tomorrow I'll pop them off and hollow. Then I can get the turtle deck sheeting on.
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The daughter is away a few days do I can make all the mess I like. So we hollow blocks. I thought I'd get some idea on weight savings of the hollowed block so the first shot is on the scale before hollowing at 28 grams.
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I put a straight router bit in the drill press and will remove the lions share of wood with it.
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Next I put in this auger ball which cuts slower but more controllably to get it down to the short hair. Then I touch it up with a course sanding sponge.
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I put the piece back on the scale and got 16 grams, nearly half what I started with. I could do a very little bit more but since I didn't go through anywhere and don't have to fix anything I think I'll just settle for it and leave it about 1/8 with a few thicker spots.
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Sigment mounts the piece and I'm on the number 2 of 3.
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Hope this shows up in the photo. On the last block I got a little carried away with the router bit and went through the block a bit. To fix it I applied some gorilla super glue then packed in some balsa dust off the router.
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Starting the deck work. Here on Capt. Eddie.
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Here on a Desperado. I'm using some junkie 1/16 sheet to make a pattern then will cut the part from 3/32. Notice the retaining tabs I glued at the top of the sides. This has proven the easiest way for me to hold the bottom edge in place while glue dries. Afterward I cut the tabs off.
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The sheet is on this side.
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Tools. Here is the cut sheet. Also an atomizer to wet the convex side and a rolled tube used the roll the wet sheet over to loosen the grain up on the wet side and start the curl.
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Glued and taped to dry.
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Starting to develop character.
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A long day but squeezing in a hour of shop time. You'll recall when I set the stabilizers on they were just lightly tack-glued on. I wanted to wait until the rear fuselages were built and stable before I really nailed them down. If needed I could crack them loose, I've already accidentally done that on two, so they could be shimmed true to the wing in the horizontal plane. Then epoxied. This is the first one and sure enough a 1/32" shim is required to correct a slight twist.
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I'm wanting to keep the epoxy application minimal for weight and I will back these joints up with carbon later anyway so I tape up for application then peel off the tape taking away all extra.
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Still riveted watching this build. I'll be ready to start my first full fuselage plane by next Winter, and your comprehensive documentation will be a valuable source of how-to information. Thanks, Dave.
Rusty
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Very kind Rusty. We are getting pretty close to completing the airframes, maybe a week or two. Have three days off this week so should make progress.
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After a great day with the fam, I stole away to the shop to get parts together to make cowlings. Really a lot of parts! The center fill blocks are 5 laminations of light wood to get to 2 3/8 width between the sides. I find a plywood ring on the air opening makes shaping more accurate and easier. Now to glue it all together.
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...
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The ply ring is a neat trick...
Marcus
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The ply ring is a neat trick...
Marcus
Makes the L/E of the cowl opening much more ding resistant too. y1
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...
Dave,
I noticed the Gorilla glue in your photo. I know some folks here use the stuff but I have yet to try it. How does it sand compared to CA? Is it "instant" like CA too? How about the consistency compared to CA, thin, medium, or...?
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Gorilla Glue sets up fast but it is not an instant bond like CA. It only works where there is no gap. It foams as it cures and while the foam fills gaps it doesn't have any real strength. The best application is in clamped joints. Works well as a lamination adhesive.
Joe
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I go right along with what Joe says. It IS my cya adhesive. It's a tad slower to set-good sometimes-and it does what I need it to. I understand it has rubber in it. If I need more strength, gap filling or work time then it's the regular cement. Also we have it at work....I can buy it there and not worry about getting to the hobby shop!
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The Gorilla Glue sand very easy for me. Of course what oozes out during laminations is easily cut with hobby knife. I also like that it expands into the pores of the wood. It will also show you every worm hole and pin hole in the sheet. Would not use it for regular gluing like fuse and wing joints.
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Today is about cowlings. These I anchor in three places, a pin in the front which inserts into the nose ring and two bolts in the rear corners to be out of the way of the pipe header. In the photo I've routed across the rear where I'm going to set in 1/8" plywood pads.
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Here plywood is cut and epoxied in position.
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Getting the 3/8"sq. motor stick pieces epoxied in for the rear tie downs.
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Getting into those little details that drive ya nuts. If you can see it there is a second piece of a 1/8" ply nose ring just behind the full ring. This section is double stick taped to the back of the front ring. Then a little 5 minute epoxy is applied to the cowl which is shoved into position against the ring section. Have to be careful not to let this epoxy go anywhere but where I want it.
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And here I'm marking where to drill bolt holes for the rear tie downs.
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Retaining pin, bolts holes and setting blind nuts.
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..
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Dave
It looks like to me you got some serious sanding and carving ahead....
Do you ever leave the shop?? LL~
Marcus
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Dave
It looks like to me you got some serious sanding and carving ahead....
Do you ever leave the shop?? LL~
Marcus
Heh-heh, think that's a lot of work? Just wait 'til prep and finish time comes around on THREE airplanes at the same time. Whew! n~ n~ n~
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Thanks for the Gorilla Glue info guys. H^^
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Dave
It looks like to me you got some serious sanding and carving ahead....
Do you ever leave the shop?? LL~
Marcus
Only when duty calls.
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Heh-heh, think that's a lot of work? Just wait 'til prep and finish time comes around on THREE airplanes at the same time. Whew! n~ n~ n~
That's what I'm doing... Finishing 3 planes... n~ n~ n~
Yours look great! A clean build. Congrats!
Marcus
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Well, I see you must have gotten the epoxy to stay where it was supposed to stay. I love it when I can see how things are done.
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I wanted to say that as I've been in the shop some this weekend my thoughts have been about our departed friend Allen. I met him poolside at the stunt motel at the Lincoln Nats, I think 1979. It's been a pleasure to know him since. My last actual conversation with him was during Nats week this year. After the qualifying rounds he set out for another contest many miles away he had committed to. He knew I was pretty disappointed in my performance in not qualifying. As I sat in my motel room that evening my phone rang and it was Allen still driving on the road but calling back to inquire about my well being. Nobody but Allen would be so interested. That's who he was. Will miss him greatly.
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I'm sure he would expect the work to go on.
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What's up with the wire Dave?
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Wayne I might tell you I'm creating a low voltage force field around the Venturi to aid fuel flow during the hourglass. By spring every glow ship at the field would have it and four articles would be written about it with graphs to prove it. But alas, the snips of 1/2 a lead out wire or .012 flying line epoxied into grooves are to stiffen the thin front section to the nose ring cowling retainer. Wouldn't take long to crack that off without reinforcement.
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And I thought it was carbon fiber tow. Looking great so far. H^^
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Great diversion story Dave but don't worry, I won't tell anyone the real story about your venturi force field secret. :##
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(thanks Wayne)
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Great diversion story Dave but don't worry, I won't tell anyone the real story about your venturi force field secret. :##
I think it has to do with the Dark Side of the Force... LL~ LL~ LL~
Marcus
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This one is getting fun.
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Off a couple days so trying to make up some ground. Got to have all these dope-ready by around the 12-13th. I will have the place to myself for around six weeks starting then and will need to completely finish all three during that time. The rear portion of this canopy needs doin' so I take a piece of card stock and form it over the area.
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Then a piece of .030 acetate is layed on and worked down with the Monocote heat gun until it follows the fuselage shape.
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Now the piece is fitted and marked for trimming.
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Ready to go.
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Rudders on the 105s.
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Shaped and painted headrests.
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And prep cockpits.
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Gramps and the Duke have a bad night.
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It's New Years Eve so the boys are getting plugged. Balsa plugs epoxied in will be cut flush and used for glueing solidly to the cockpit floor. Hopefully they'll stay put.
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I like the pilots. Well I also like the planes.
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The cockpit complete and pilot mounted. Now the canopies are glued on with cement. This is where you hope you got the dust out. Shore get mad when you didn't!
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Looks good from here Pilgram.
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This canopy on, one more to go.
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I have sure beat the thunder out of this nose block on the table. I'll wet it and let it swell back out. Pretty soon I'll be doing all the work with a pad on the table.
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"Just get on with it ya x!$o,@!!!"
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Last frame this evening. Here is Captain Eddie with electrical tape used the mask the canopy for the finish. I usually change this once, right after the color is applied just before final clear coats. That's a good time to fix any problems.
I think I'll be ending this build thread in the next few days after I show my fillet technic and final prep for finish. I won't be taking it the finishing section. I'm going to have to cut some corners on the finishes and there are surely others here who have more skill and patience for the finish than I. I will post photos here of the completed airplanes when I get there. Tomorrow we'll be doing some stuff with carbon.
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Great, I'm glad you're going to show us the fillets, because I'm about to try making some nice ones soon too.
I hope Cap'n Eddie doesn't get too freaky about being sealed up in the dark and punch out. LL~
Rusty
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Great, I'm glad you're going to show us the fillets, because I'm about to try making some nice ones soon too.
I hope Cap'n Eddie doesn't get too freaky about being sealed up in the dark and punch out. LL~
Rusty
I'm sure it's dark in there. I've given a new name to Capt. Eddie's ride. It will be the 'Asteroid'. I just hope it's not a dumb space rock. The Captain deserves better.
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I caught another wind and did a little more last night. I dressed the cowl lines some. Here you can see I applied clear plastic mailing tape to one side of the fuselage cowling juncture.
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Here I apply a little feather weight spackle along the edge of the other piece.
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Now the cowling is carefully put in position and screwed down snug. The excess is squeezed out and I push a bit more back into bad spots with an old plastic gift card. (Or those blasted AARP cards I get in the mail about once a month).
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...
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The final result of the cowl line work.
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The Patch n Paint filler is pretty soft with no real strength. Once sanded to my liking it is coated with Gorilla Cya which soaks in and holds it together.
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I got the scale out to get some idea where I am with weight on these.
Asteroid ready for dope is 30.6 ounces.
Both the Desperado 105s are 31.5 ounces.
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I was going to ask you about that Patch-n-Paint stuff. I have used the other junk and put CA on it.
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John it works OK for small stuff as long as you know it has no strength and if you try to use it in concave fillets dope will lift right off and give you a blister. It weighs nothing though and sands super easy so it works once you understand it's shortcomings.
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I'm liking this stuff for where I have a larger gap and need strength-a lot of strength. Cut off a slice, knead it a minute and apply. Rock hard in 15 minutes and I mean hard! Grind or file hard. You need to get it smoothed out pretty close before it sets.
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Here's where I used a smidge to fill in behind a nose ring.
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Now I'm getting prepared to carbon the fillets. What fillets, you say? Exactly. Large radius fillets are aerodynamically not great but really no big issue on our scale. But I no longer make them because of all the fits I've had over the years trying to keep dope stuck down to them and not blister up with shrinkage. The best luck I had with that was carved balsa fillets with silkspan Cya'd down on them. This provided a little 'fingernail' for dope to grip. All forms of resin based filler give nothing to grip on to. Epoxy is the worst. A few light dope coats will stay better than a top notch finish because there simply isn't enough total shrink to hurt too much.
When carbon tissue came along it was my answer. I can shove it into the joint for great strength without much weight. Then it sure wicks up dope and won't turn loose. Finally, once the fluid medium is cured in the carbon it won't change shape. In order to lift and blister it would have to change shape. I haven't had a single issue with fillet lift since I started doing this.
The first shot shows the tools including clear dope, .5 carbon cut into strips about 3/4" wide and an old plastic gift or credit card used to ram the stuff in.
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This is exactly why, if you'll remember, I epoxied the wing/ fuselage joint on the inside and tried to keep epoxy off the outside surface.
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Apply some dope, lay in a piece and ram it in the corner with the card. Apply another coat of dope. Move on to the next piece and on around. The pieces need to get pretty small going around the leading edge. Don't worry about overlaps- they sand.
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Here's a shot of the first fillet complete.
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Here on the stab. Eventually I'll also lap the canopy with it too.
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A pretty productive few days. All three are in carbon mostly and spackled up. Tomorrow I start sanding.
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Wiky lerks photo. No additional info available.
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Thanks Lauri and yes keep me informed. I'm actually looking at three (at least) different systems right now or some combination of them. I think each of my three new airplanes will have something different. I think electronic will be more reliable but at least with mechanical I won't need to carry batteries. The hardest thing so far to develop is the actual pinch off that works with light activation but enough force. The servo route makes that easier. We'll see.
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Lauri if you don't mind, make me up one of your systems when you get back and send it my way. Gladly pay you whatever. If I understand what you have I could only use it in FAI and not AMA but FAI is where the gremlin is.
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Ok but I cannot give any estimate when it is ready. I have a new engine coming, hopefully it's ready for Poland.
The electronic parts, receiver & transmitter, you can get from Ken Bauer.
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Sounds good Lauri.. Now I just need contact info for Ken Bauer.....:):)!
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Check his website:
mysite.verizon.net
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Found it. Thank you!
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This will really speed up the flight trimming process too.
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Yes, that's the reason why I use it. When testing our very powerfull engine that has a very low fuel consumption even at rich run. I got bored at flying 13 minutes with 4 sec. laptime when something went wrong. It saves the engine and airframe.
Actually, even when FAI rules allow its use (don't know about AMA), I don't find it so important in competitions. For sure I will use it but I've never really had issues with engine stopping too late (knock-knock..). I will still continue to fill the tank for 6.5 minutes flight, just in case.
There are other benefits than just avoiding overtime, like a possibility to choose the point where the engine stops, it is very usefull in strong wind. Often the engine likes to stop when model flies against the wind and that is not good for landing glide. Also, as the engine does not get the last bubbly fuel in the tank, it will not go lean in the end and stops more quickly. That's also good for landing glide speed.
My clamp is mounted be in the 10mm wide space right between needle valve and tank front end. You can see the mounting holes in the tank mount. I think thats an ideal situation but I don't know what the effect will be when the clamp is further back from the carburetor.
With front intake engine, the device can be bolted in to backplate or mounting lug for example. Receiver, servo and battery are just in front of bellcrank.
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Y'all probably already know about it, but since you haven't mentioned Hank Nystrom at Texas Timers.com, maybe he's a useful resource for these types of devices. The only reason I know about his Free Flight site is because that's my source for fine thread needle valves and bladder materials.
Rusty
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Thank you Rusty! Hank built the unit in my photo and we have been working on the project. Great guy. If I can make this work well Hank might make me a run of purpose-built units. Right now we are plowing ground to see what sprouts.
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Just to show I'm not sitting on my duff thought I'd show the machines are in grey undercoat and today I'm using the spot putty to fix bad spots. Should start spraying white by this afternoon. The grey is just the fourth coat from dry tissue! Light! In the foreground is the Merco Black Streak .35 I found to go in the Warburton Tony I plan to build as a classic project. I'm pretty sure this is the type engine Frank Warburton had in his Criterium winner about 1963.
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...
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Ah, great. Thanks for the update. Just this week I was just thinking about this thread, wondering if we were going to see anymore. I remember you saying you didn't plan to post minute finishing details.
Rusty
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Ken Bauer's email is: airtek at verizon dot net
I tried the address Lauri posted and only got the home page for Verizon News. And, I applaude your efforts for doing battle within the FAI rules. Timers are legal in AMA stunt regs. But, I would also suggest that with our 8 minute rules that it's relatively easy to get the flight time adjusted by only adjusting fuel load, and it's probably better (IMO) for the lower skill classes not to bother with timers and R/C cutoffs.
As an alternate, there's been some work in the past done on tanks that shut off the engine after too many laps of flying upright. Basically, if you're running an engine that needs 6 oz to do the pattern, you'd get a 7 or 8 oz tank and install a small wedge tank inside. The tank is installed inside the big tank, and has holes arranged in it to allow fuel in, but only in some positions. The feed line and uniflow line would go into the small tank. How big that tank is requires some experimenting, of course. Some calculations would help narrow down the size required for the small tank. One of the benefits of this deal is that you could move the small tank up/down inside the big tank, to adjust your engine run for inside/outside equalization. No, I haven't got it all figured out, and since I have no plan to enter the NATS or fly in the TT's, I don't really need to. But I do like the concept a lot better than adding mechanical or electronic systems. See the two attachments. H^^ Steve
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Very interesting about the tank Steve. I'm pretty fussy about my tank set up tho and would rather not mess with what is working good at least for me. Actually getting an engine stop within eight minutes for AMA is usually not too hard unless something causes a lean run like trash in the spray bar or a pipe leak. My greatest interest in this is for FAI rules where you get 7 minutes and not one extra second. Here a slight weather change or insect down the tank plumbing ( or a simple error) can ruin a two year program. However it would be nice to short-run during the trimming phase with a new airplane or to shut down when something goes wrong.
I too found that Ken Bauer must have quit. So for now I have a couple other ( unnamed to protect the innocent) sources building autonomous electronic units for me. I also already have a supply of the 2.4 gig radio units built and on hand ready for post-2014. Thank you Nick Leichty. I will say you shouldn't add any complication to your AMA stunt endeavors for this year. You can grow and harvest a crop in 8 minutes. But we'll have to see what develops after that. You can be sure some change is at hand!
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No, Ken has not quit, maybe his time just is limited because of real work. But for sure he is making the RDT units. I will get new ones next week in Lost Hills.
I recommend sending an email to him.
As I wrote before, the main point is not to stop the engine with a presicion of second. More important is to be able to stop the engine in right place, and also with shut off, the engine stops more quickly and does not kill glide speed. When all is working well, my run times without shut off are same anyway, within a few seconds. L
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Yes you are right about the stopping points. When you talk to Ken please direct him my way. All efforts to contact him on two web addresses have failed. Maybe I'm doing something wrong. Give him my email.... VegasDave4@gmail.com. Thank you Lauri!
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Looking good Dave! y1
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All stop!! Have to strip and recover all three airplanes. I used Lite Flite Plyspan to cover the open bays, light silkspan everywhere else. On just the Plyspan the dope started to delaminate when I started to spray. Very strange. It's fine over the silkspan. It's like the Plyspan was waxed paper. The regular or super Plyspan doesn't do this but has a whole different feel and texture- no slick side. So I recover.
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(snip) In the foreground is the Merco Black Streak .35 I found to go in the Warburton Tony I plan to build as a classic project. I'm pretty sure this is the type engine Frank Warburton had in his Criterium winner about 1963.
Hi Dave,
Actually, Frank used a Red Head Merco from the early '60s. The Black Head is a later model and as you probably know, there have been several owners of "Merco". There were quality issues off and on during the time. The latest Rustler-Merco (Ian Russell, a member here) are excellent engines. The early Red Heads were excellent stunt.35s of the period. A bit more punch than a Fox .35. The Black Heads varied from good stunt engines to unusable engines.
BIG Bear
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Hi Bill! It was a ( bad) guess on my part. Well, so was the covering. This Merco feels pretty good and doesn't look to be run very much so we'll see. Didn't give too much for it. When I get going on classic I'd like to keep the engines pretty close too. Hard to understand putting a piped whatever in a 60s classic. Sort of lost the point. If this doesn't work I've got a half dozen Enya .35s looking for a job.
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Hey Dave I hope you are painting in a well ventilated room. I don't spray in my shop, I do brushing of dope instead.
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John I don't have anywhere to spray but I have a big box fan blowing out when I dope. It does a pretty good job. I use nothing but an airbrush so the cloud isn't too big anyway. But this is the main reason I have to get these done very soon before the daughter and baby move home. Maybe 4 weeks or less. Think I'll make it? Having to pull the covering back off didn't help. Thank goodness Hobby Haven had a fresh batch of Super Plyspan in. Thought about using the light silkspan I have but it starts splitting when the dope gets really hard and brittle. I've used a lot of the super and like it-just was trying to cut a little weight... Silly me.
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Hi Bill! It was a ( bad) guess on my part. Well, so was the covering. This Merco feels pretty good and doesn't look to be run very much so we'll see. Didn't give too much for it. When I get going on classic I'd like to keep the engines pretty close too. Hard to understand putting a piped whatever in a 60s classic. Sort of lost the point. If this doesn't work I've got a half dozen Enya .35s looking for a job.
Let me know if you want a good Veco .35S. They were about identical with the Red Head Merco. Pretty strong for the "old" engines. It was the strongest of the old USA .35s IMHO. The run of the McCoy .40 was great, but the problems they had made them iffy, or else you bought a "supply" of them so that you wouldn't get caught short.......... this can be "cured" in these days, but not much luck back then.
BIG Bear
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The Veco sounds interesting Bill. Let me know what you want for it. I have one that I bought to go in the Veco Hurricane kit I found but another would be good. Unless you want to trade something....looking for anything in particular? I'm deep in many engines other than Fox or Tigre.
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'sorry, Dave. How aggravating!!!! I admire your perseverance! 'looking forward to eventual success.
SK
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Thanks Serge. Sure is aggravating. I think this is why I usually stick to old proven ways. However if we don't try something new once in a while....... In this case it's also about finding reasonable alternatives to losing the medium silkspan we always had at the hobby shop. Makes the all- sheeted wing look more attractive though I hate throwing another five or six sheets of wood on the airplane for no reason other than covering space. The heavier Plyspan works well but just soaks up more dope. At least I know it will last and not start popping apart like the last light silkspan job I did. Split wide open while just hanging on the wall. It's also aggavating to have to work all weekend and not get anything done in the shop! Coffee ready yet? Ggrrrr....!
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I don't think you have to take a big weight hit with fully sheeted wings, and they're potentially better shaped. However, I don't like the prospects of repairing them after my inevitable mishaps, many of which only tear some silkspan, but would buckle or fracture the skin. I'm still tempted.
SK
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You know the part about wing shape in regards to full sheet vs. say open bay or I beams might be a great
topic ( should you accept the mission) over in the design board. In our scale I don't think it matters too much. In fact years ago I built mostly I beams and thought I was gaining something with the slight channeling of air flow. Sure know the Werwages and Sheeks of the world liked them. I actually stopped when the women in my life said they didn't like the 'bumps' on my wings- seriously!
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I tried SIG Plyspan on a FF and didn't like it at all, as I recall. Probably took it back off and used something else.
Time for Mr. Trible to get some Polyspan! H^^ Steve
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Yes maybe. Don't even know where to get it. Actually I'm intrigued with the Thai silk thread. Haven't used silk in a generation but might do that again. Thinking.....I know it will get brittle and split too but it takes a long time.
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Just making sure I'm not looking at a mis-spell above, are we talking Plyspan or Polyspan? I only use Polyspan and the stuff works great.
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Wayne I'm talking about Sig Plyspan. The super is pretty good, pooh pooh on the Lite Flight. It's not a thinner version of the super. It's something completely different. Covering with super today and looking good.
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Thanks Dave, good to know.
BTW, what did you use to strip the covering?
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This wasn't too bad on these for a couple reasons. The lite Plyspan is actually pretty tough so I could pull it off in big chunks. Since it is so dense dope never gets all the way through it so when applied, the wood is prepped with dope before hand then the tissue is attached with thinner which will go through. That being true then a simple re-wetting with a brush full of thinner loosened it. There was just four very thin coats of dope on them so the thinner got through in a few seconds. I've done a few and may do a couple more with thick, hardened finishes that required an acetone bath with six rolls of paper towels and a gallon and a half of acetone. Those are nasty but can save an old or heavy airframe.
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Ah the smell of castor......got in the first two patterns for 2014. Flying called due to sleet. FYI, all three new ships are in white base color as of this morning.
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8) 8) 8)
Marcus
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Was it a little muddy? I have pondered on going out too, but wonder about the ground. At the Knorthern Knights field we had to move the center a couple of times one year because of mud. Can we get permission to lay some cement blocks down for a center pad? The ones I put down at the KK field were on close out at the time. I think Tulsa uses a septic tank lid for the center. Also I did not hear my phone ring!!! VD~ VD~ VD~
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John about the phone....thought you were still in Texas and wasn't sure if I'd get out of the dentist early enough to even go. Won't happen again! The field was a little soft but do-able. Some mud patches at the center. I'm going to get some grass seed. Still see our oil spots from last year but you still see the mowed line around the circle. I'm not sure about putting something down in the center. I'll talk to Robert, our contact there about it. He actually stopped by here at work to say hello earlier. It is flyable now though weather willing, if you don't mind muddy knees!
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Igor... New Norden bomb site.
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I like the idea of a precast concrete septic lid ... Good idea by somebody.
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Igor... New Norden bomb site.
Dave,
Can you give a little explanation on these guys?
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I think Tulsa uses a septic tank lid for the center.
A septic lid for a center circle pad? Ironic. :##
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Dave,
Can you give a little explanation on these guys?
Doug I'm not quite ready to give a full run down right now. Still pulling
'Briddled Thunder' together and needed those working on the project on the same page. Just imagine your IC airplane with an accelerometer, idle and shutoff.
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I like the idea of a precast concrete septic lid ... Good idea by somebody.
Give credit to Tulsa Gluedobbers.
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is it done yet?
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is it done yet?
No Robert have a ways to go. Dub got his part done ahead of the rest of us but needed to so we could set some parameters for the rest. That's what you see. My ships will have two separate electronic systems on board. The 2.4 which is ready to install now but will only be used in practice this year and Briddled Thunder which we are still working on. In Tampa for a family matter this week but when I get home will start some bench testing with the .76s. My cohorts will be testing other parts and I will marry the mess in the new Desperado 105s and start testing at first good weather.
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Igor... New Norden bomb site.
So here comes stuff for bombing.
Version #1 is based on my programmable timer / sequencer http://www.netax.sk/hexoft/docu/itimer_en.pdf
Picture shows whole system. Timer powered by one cell batery controlls servo connected to choke valve. Timer can be programmed to make different programs, simple full throttle for periode of time, then cut or idling before / after flight, or even landing for low throttle and again start (for semiscales) etc.
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And here are components. All can safely fit under 1 oz.
From upper left corner down:
Timer, Y cable, one cell lipo battery, nano servo, conversion cable for battery, switch.
It will need jetibox and source 5V for programming, because 3.7V is too low voltage for Jetibox.
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Version 2/
Based on active timer with accelerometer as used on electric motors. http://www.netax.sk/hexoft/docu/iAccTimer_en.pdf
It will controll RPM by servo like I wrote before. It does not have tricks with idling (at least not so far). It will need higher voltage, because of servo speed and force for accurate valve controll, so it will use 2 cell battery and 5V BEC module.
Whole system is on Picture.
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components:
Timer with accelerometer, Y cable, servo, 2 cell battery, switch, and 5V BEC - Actually I did not have small BEC, so I used small ESC, it was smaller and cheaper then dedicated BEC.
also programmable by Jetibox which could be connected between 5V sorce and timer.
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All that stuff above worked on my desk. I do not see problem with verion 1/ however I am not sure how will version 2/ work with 4-2-4 motor and that simplified carb. Well ... we will see :-)) ... Hopefully Dub knows what he does :- ))
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Yeah. And the goofball who is going to try using it all!! Thanks Igor.
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WOW!! This is going to be interesting!!!! Cant wait to hear how it works out!!
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The timer itself work well in wind with electric motor, I flew in 16m/s wind in Bulgaria according spectators standing under anemometer. What it does witm engine reacting to longitudal acceleration (fuel pressure and probably load as a result of slowing/speeding) is question which I wrote I am not sure. But accelerometer is sensing that accelration causing those changing, so if I cannot manage it automatically, there is still way to make some compensation in algorithmus.
Basically it is exactly like we do it with electric - I set basic speed and amount of +/- RPM from that base setting. The same is doable here, just basic rpm is not set by number in timer, but needle setting instead. I do not see teoretical hole in that system, we will see what will reality do :- ))
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Question:
When the model likes to speed up, do you want to choke the venturi to slow it down or make the engine run richer?
I have a feeling that that system may work in ideal conditions but not in strong wind.
But interesting it is.
L
Lauri I'm not sure how good an answer I can give. From a practical standpoint I think it easier and 'quicker' (very important for response time in our application) to manipulate the air volume and not directly adjust fuel volume which is also a little slower response. However our gadget does passively reduce fuel simply by reducing airflow and thus draw of fuel even though we aren't doing anything with the inlet. It would not be too difficult to use this to tweak a needle setting but my thought is that would not be good for active speed control. Probably too sensitive as well without some fancy fuel metering system. Sure somebody will say it can be. Guess I'll let 'em. I've already bitten off a big bite for me now. You'd probably need to read shaft rpm range and tweak the fuel flow or needle when it fell either side of your chosen parameters. To actively or remotely do so would fall outside AMA rules. If it were an onboard programmed function then go for it. Just don't be doing two outside triangles in some strange place in the pattern. The circuit cops will figure you out!
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.....
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More pics!!
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Not yet but soon. Progress is finally happening. Last of the trim colors on all three today and touching up. Will start inking tonight. Then just about three coats of clear. Not very much to rub but they feel pretty light so far.
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....
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WOW!!! Looks like I should have bought some stock in 3M. :##
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WOW!!! Looks like I should have bought some stock in 3M. :##
Boy no kidding Wayne. Actually a lot of Contact brand too. All the fine strip and stencils I cut from self-adhesive shelf paper. Many hours. I'm usually glad to get finished. I'm real pleased with weight so far. Looks like all three are 4-5 ounces lighter than last year's fleet. Especially impressive with the 105's which are in fact 5% larger with more area to cover and paint. The wing loading goes well down.
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The plane looks great Dave, cant wait to see it and you in Muncie!
Derek
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Test flights in Topeka when they are ready? I know the grass field may be a little rough after this past winter. Planes are looking great, be glad to see them in person.
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The plane looks great Dave, cant wait to see it and you in Muncie!
Derek
Hey Bro!!!!! Thanks a bunch. You reminded me my entry forms are still laying on the table..... See ya there.
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Test flights in Topeka when they are ready? I know the grass field may be a little rough after this past winter. Planes are looking great, be glad to see them in person.
Well John we'll test here. These first flight sessions are often one or two flights then go home to fix something. Hate to drive to Topeka until I'm ready to work on ME instead of the airplane. If we can get weather I'll be ready to start flight trimming in about two weeks. Will do this with limited electronics on board- maybe just the 2.4 shutoff.
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Well being fully retired I almost went out Monday, but this being not on a schedule I slept too late and it was time for picking up kids. I did get some time in the shop.
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Well being fully retired I almost went out Monday, but this being not on a schedule I slept too late and it was time for picking up kids. I did get some time in the shop.
Yeah so rub it in! Excuse me, I'm getting ready for work....my employer doesn't seem to understand they are getting in the way of my flying.
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Now you know why I spent so many years putting my time in on the Midnight shift.
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More pics?? ;D
Marcus
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More pics?? ;D
Marcus
Marcus at this point they wouldn't add much. I'm doing ink lines now and will be getting clear on over the next week. When that's done I may take them out in the daylight and get pics of all three and post. It will take a few more days after that to get new tanks made and installed. Then I still will need to figure how I'm going to mount two micro servos and the rest 'electrickery' in. Maybe I'll get some shots of that. Stand by!!!
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Capt. Eddie 's Asteroid before clear.
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Dave I'll be cherry picking info out of this thread as I build my next stunt trainer, a much simpler Brett Buck style Skyray, but there is plenty here that I can add to my knowledge set. Hope you don't mind if I have a question now and then.
First up is the rib balsa. My ribs are 3/32" and I have some average light balsa and also a beautiful sheet of contest balsa. Considering this plane could pancake at the bottom once or twice as I learn(I'm mostly past that), do you think I should use that contest wood to make the ribs, or would I be safer with a bit denser balsa?
Thanks,
Rusty
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Hi Rusty. I'd say as long as the light wood is stiff enough to hold shape and resist warpage (and 3/32 will be) go with the lighter construction. Build for best flying and not impact. Impact will likely bust something anyway so go for better flying. Maybe that will help keep you out of the ground. My ships tend to be a bit heavier than they absolutely could be but I build to deal with a life on a rough flying field. Finding a good balance in that is hard sometimes.
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Thanks Dave. That's what I sorta figured the answer would be.
Rusty
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Hey Bro!!!!! Thanks a bunch. You reminded me my entry forms are still laying on the table..... See ya there.
OH CRAP! So are mine. Better get on that!
Derek
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I thought I'd show the 2.4 ghz. shut off system going in the Asteroid. From the top; 100ma LiPo, receiver, switch, 9gr servo. The fuel line passes through a wire loop on top of the servo which is twisted shut on activation. Charges with 4 AA pen cells. Good for a whole flying session on one charge. For competition flights this season I'll pull the LiPo and simply not loop the fuel line through the servo.
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...
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Your tank is completely sealed off? You cant get to it without cutting?
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In this case that's true Doug. I install my tanks usually with one block epoxied in to hold and maybe a little silicone. No it's not an instant change but I can change it in thirty minutes. Never so far needed a 'contest change' but I still could if I had to. Once I get things set up early on its usually good to go. Most removable setups I've tried have let me down at some point but I know many have good ways to do it. In this case it got ugly making room for the switch and mounting the servo in a usable spot. Yes it would be bad news if I needed to pull this tank but I still can do it and back in the air in about an hour if I had to. The programmed system I think might be a little easier because I can mount the servo elsewhere and run a pushrod forward to the carb. I thought I would use a fuel pinch gizmo I made with the servo mounted back further but found that got hard to do with the servo way out of line with pinch device and arm movement a problem with the pipe header in the way. This would be easier with a muffler. In mock-up this looks to work but need to figure out how to get the servo reversed to get a better pinch on the line.
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This one is ready. Two more to rig out.
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That color scheme makes the stab/elevator look big.
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....
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Well short of sealing the hinges and some bench trimming all three ships are now ready to test fly and trim. This will be done in normal fashion without electronics. Actually I'm going to do the initial work with that stuff on some older machines to get it working well and not risk the new airplanes until I'm sure the electronics are fail safe. With that I'm calling this thread complete. Thanks to all that followed along and I hope we all took something worthwhile from it. It truly WAS fun!!!! See you on the Lpad!
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Your thread is a helpful reference for tips and info. Thanks.
Rusty
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Tale of the tape:
Asteroid. 660 sq. in. 67 ounces.
RO Jett .61. Randy pipe. Mejlik props
Desperado 105. 'Gramps'. 700 sq. 69.7 oz.
RO Jett .76. Randy pipe. Brian Eather props
Desperado 105. 'Duke'. 700 sq. 70.4 oz.
RO Jett .76. Randy pipe. Brian Eather props
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And they use REAL engines!!! ;D
Great job Dave, keep 'em coming. y1
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Thanks for all the info and helpful data plus the pics.
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As epilogue I test flew Asteroid last week and am pleased with it. Some yaw to trim out and put in a new tank. This morning I test flew Desperado 'Gramps' and am very happy with it. Full pattern on flight two. Best airplane in the vertical manuevers I've ever flown. Headed back out with Desperado ' Duke' for its maiden flight. Here's Gramps on the field.
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Beautiful. Thanks for the flight report and picture.
Rusty
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Thank you Rusty! Here is Duke being made ready for its first flight. Another superb airplane!! I've never been so lucky (or blessed) to get three great airplanes in the same decade, let alone the same year. Interesting both Desperados needed the same flap tab tweak. Me thinks its to counter the torque of the .76s.
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OOOOOOOOOOOOOOOOOOOOO!! That is one sweet combination of colors!! Wow, do I like that! #^ #^ #^
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Thank you Will!!
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I see Duke has a four blade prop. I'd be interested to know any flyability differences.
.76s, eh. I'm about to fly my first plane in this category, a Magnum(maybe not quite as big), and am frankly worried about hanging on to it. Never flew anything bigger than a .35, and I only weigh 125 pounds. Will I need a pole and a safety belt?(http://i166.photobucket.com/albums/u116/rknrusty/Smileys/rolleyes.gif)
Rusty
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Rusty I'm size-challenged myself but don't worry. It's more about airplane weight and speed than engine size. Bigger airplanes might wear you out at the field a little faster though.
The four blade prop is nice. It just seems to run a little smoother. Thrust? Not noticeably different than a three. One must get out of the way of it one blade faster when starting!
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A peak under the hood of the accelerometer system going in the test airplane. When I took this shot I was waiting on the LiPos and a voltage regulator to arrive so they aren't in the photo. Trying a 2 cell 180 mah LiPo and have a 350 if I need more. One of my .76s spun a bearing so I may do the early testing with a .61 while the engine gets an overhaul. I'm wondering if this system will actually be more useful with the .61 anyway. The .76 pulls through the pattern in a flat four cycle at a constant speed up, down or level as much as I can sense and so I'm not sure what I'm regulating. The .61 however can be 'goosed' under load to maintain a better maneuver shape. We'll see.
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Sorry to be rules lawyering at this late date (and forgive me if someone's already posted on this). The FAI sporting code, section 1.3.2, does indeed allow radio shutoff in control-line aircraft:
1.3.2 b) Powertrain control may be accomplished by the pilot via the wires or cables or by an onboard self-contained, automatic process.
But the aerobatics-specific code, section 4.2.2, seems to very emphatically rule it out:
4.2.2 e) The use of a pilot activated power shutdown device to define the point of the beginning of the power-off descent in the landing manoeuvre is not permitted.
This certainly seems to toss a wrench into thoughts of using a radio (or inertial control) to shut down a motor in FAI.
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Hi Tim. I sure stand to be corrected but I'm under the understanding they already do use the 2.4 in FAI in Europe for shut off. Lauri Malila and I have had discussions about doing what he already does routinely. Might be like our own rules; technically AMA would allow the 2.4 for our use now but 'aerobatics' hasn't specifically opened the door to it- until this new rules cycle proposal. Would be interesting to know if there is an updated amendment someplace there or could they have now disallowed it? I can see where the seven minute FAI time limit would make the use of a shut off much more an issue for IC since electric timers made it a non-issue for electrics yet still some challenge for IC .
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It's new: in the front matter of the code it's mentioned as being implemented for the 2014 sporting code. It may well have been implemented as a response to the use of the radio gizmos in 2013, but you'd think that Laurie would know of the change if so.
I'm certainly not the one to correct you: one of the facets of being human is that there's the rules as stated and the rules as read, and the rules as enforced. I read the rule as disallowing radios, or third lines, or down-elevator cutoffs, or using the characteristics of your fuel tank for a cutoff loop, etc. How that rule will be enforced by FAIens, and whether it'll be enforced differently at "local" contests vs. the WC is well beyond my ken.
If you have a timer, and you know exactly when your plane will shutoff, you could in theory doodle around to pull the shutoff point back in the circle, or fly high to push it forward. The timer would remain "autonomous" per the new rule, so you could still effect shutoff where you want it (with some skill on your part) while cleaving to the letter of the law.
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As I wrote in rules section:
http://stunthanger.com/smf/index.php?topic=33941.msg353733#msg353733
Radio cut off was ment from begin as an emergency tool especially for combats for cancelling flight, the same way as in FF. So it should not be used for controlling landing maneuver. However I do not see how it should prevent usage of TIMERs.
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As I wrote in rules section:
http://stunthanger.com/smf/index.php?topic=33941.msg353733#msg353733
Radio cut off was ment from begin as an emergency tool especially for combats for cancelling flight, the same way as in FF. So it should not be used for controlling landing maneuver. However I do not see how it should prevent usage of TIMERs.
So, is anyone trying to use radio for a cutoff in stunt in FAI, and are they getting away with it? I'm not sure whether it's realistic or cynical to even ask -- I fear that it's realistic.
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I did not see anyone to use any remote cut off on FAI stunt planes. And I do not see any reason to use it myself. I have timer, everything works well, but I can imagine it could be good thing for beginners (in case of crash, in case of inability to continue etc) but I do not think it is any issue for F2B rules :- ))
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A shot with all electronics on board, pre-programmed and checked with the Jeti box (thanks Igor!) and now waiting to be packed into the belly with Velcro and sticky foam tape.
Inside the fuse; top left, accelerometer sensor
top right, ubec
servo and switch
Outside fuse left top; Futaba 5v regulater
left bottom, timer on end accelerometer sensor
Outside fuse right; 180 mAh 2 cell LiPo
bottom, charge lead
I think on future builds I might build compartments for this luggage in the wing roots outside the fuse. Even though I have a charge lead I am still going to remove the battery for charging. No reaso to chance lighting up a good airplane. Still a few weeks out before I'll know much about how well this works. I want to flight trim the new machines pretty well and have some fit issues with the gadget on the engine. Would also like to test that out on the motor test stand before it goes in the airplane. Then we'll get this airplane re-trimmed some and go for a system calibration flight. Then we can play with servo inputs and go from there.
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I also got the phase 1 system less accelerometer set up in Asteroid today. Really all I had to do was pull the 2.4 ghz receiver out and plug the programmable timer in its place. Then I programmed in a simple flight time and shut off servo response into the timer ( 6 min. 5 sec. Flight time with a 4.5 second servo turn at 98% travel.). Could plug the radio unit back in and change nothing if wanted.
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Dave, do you have any protection (some shielding or so) to protect all electronic components from pipe heat?
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No not yet but I am concerned about it. Thought I might cover everything in aluminum foil. Do you think that will be adequate? Open to ideas.
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I would think of something different than aluminum foil for insulation. You need something that doesn't transfer heat.
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I would think of something different than aluminum foil for insulation. You need something that doesn't transfer heat.
Aluminum foil would make a good heat shield if you had a source of cool air for the electronics. Ideally it'd entirely or largely keep the hot air from the pipe from going past the electronics. If you could keep it clean you'd want the shiny side toward the pipe, but I suspect that after a season's accumulation of fried-on castor droplets, you'd be better off going shiny side toward the electronics.
Just wrapping the electronics in aluminum foil and hoping for the best would slightly slow, but not at all prevent, the heat from transferring.
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It would seem with this system you could eliminate the pipe. Using a can muffler in its place. You are no longer using the boost/restriction from the pipe. Then place the electronics in a compartment behind the exhaust area. Only thing in the heated area would be the servo and the wires. Using a sub-micro servo would be more than enough power to run it, but you need to make sure it can take 7.4 or you fry it about 2 minutes in. A simple in-line step down cures that issue so you can still run 7.4 to the rest of the system if it needs it. The sub-micro is so tiny it can be far enough away not to get hot. The wires can be tucked away as well.
This is going to be interesting for sure.
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Doug that is a thought about removing the pipe... I have a rear exhaust muffler. I'm not quite ready to surrender my pipes yet though. My thought for now is a small range in power adjustments of maybe just a few hundred rpm. Maybe as I gain more knowledge and confidence that the engine will respond fast enough then I'll give the system more latitude. I'm going to try the foil. My pipe tunnel is really wide open with the pipe totally exposed. I think it will cool well enough in the air. My concern would be after the engine quits and heat just rises up into the electronics for a short while. The voltage issue is why we went with the 5v regulator. We needed more than the single cell LiPo would give for active regulation ( but is fine for the phase one system) but 2cell batteries were 7.4 volts. The Jetibox needed at least 5v to program either system so the regulator became nessessary. Phase 1 timer was programmed out of the airplane with 5volts then plugged into the airplane. The other system can be done in the airplane, though I'll pull the LiPo out to charge where I'm OK with charging the single cell in the bird.
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Just to be clear, as Doc pointed out, aluminum foil will bring heat To your electronics From the hotter pipe, not the other way. Aluminum is the heat super highway from a hotter place to a cooler place.
Rusty
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I'm still open for ideas on this Rusty. My thought is at least there will be some shield instead of none. There isn't much room for anything thick between pipe and gear and can't weigh much. One continuous sheet of foil laid loosely on top of everything front to back would seem better than nothing. Still listening for something better....
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On the foil: it can act as a heat shield, but not as an insulator. It'll stop convection if it's wall-to-wall, and it'll stop radiation if it's shiny. The "stops radiation" is why "space blankets" are shiny, and that's why they work.
If you look at the old pictures of the Gemini capsule in space, you'll see that the back of one of the sections was covered with gold foil -- that's because gold reflects infrared, which makes it a heat shield.
If you were to put the foil in contact with the electronics and all that in contact with the pipe, then you may as well not have the foil.
A thin balsa wall, with aluminum foil on the pipe side, shiny side toward the pipe, will provide insulation, it'll bounce the infrared back toward the pipe, it'll be light, and it should be easy to mount. Think on that...
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OK well maybe I've got something. I have some roll cork shelf liner just under 1/16" thick. It's very pliable and easy to work with. To that I can glue foil on one side. This I can stick down with the sticky foam tape on top the electronics. Sure I'll tear it up when removed but I have yards of it to use. Maybe this will make everybody happy!! LOL!
Oh it's self adhesive. Even better to attach the foil.
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I manufactured the new space insulating material. The cork with aluminum foil skin. I really do think it will work. I'll try putting it on the Asteroid tomorrow.
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Doug that is a thought about removing the pipe... I have a rear exhaust muffler...
Your pipe is going to react faster than throttle response ever will in our application. If using a pipe and the accelerometor one could confuse the other?? Maybe....
The engine is still beholden to the laws of physics. Our electric brothers are not. So when you point the nose up the motor is going to feel the added load and it will break on its own regardless. The pipe reacts faster due to the change in soundwaves from the increased rpms.
The throttle response will be different. By removing the pipe and riding on a muffler you could run a setup that breaks pretty strong in the corner then the accelerometer shuts it down with the choke to get it back to the normal operating rpm. I don't know the ins and outs of it but I think you can set how long it waits to respond so you could fly the corner and shut off the break, and vice versa,,,, going to take alot of programming and test flying to get this just right. Should be very interesting for sure.
What exactly are looking to achieve by using both pipe and accelerometer??
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Doug there is so much to be learned here. In fact the accelerometer could prove not to do much for us but the programmable timer application will be very useful. Something I was surprised to see was watching video of my own practice and also a number of team trials flights. When seen especially in slow mo you can see just how much the airplanes slow down at the tops of loops and in verticle manuevers, even with the pipe doing its thing. Obviously heavier airplanes, less power and slower lap time exaggerate the slowing. The speed itself isn't the issue but what it does to manuever- or the illusion of manuever shape maybe- is. If the airplane can keep most of its speed the manuever should be easier to keep round for example. You shouldn't need much correction through the manuever due to changing speed, ie., lift and centrifugal force during a turn. The pipe sure does this to a large degree but not quite enough in some circumstances. My project would be to give the pipe a little help. As I mentioned earlier my .76 airplanes which are lighter this year don't seem to need any help but the .61 or any set up that doesn't yield the horsepower of that .76 could be helped quite a bit if this works. Will it make you fly a perfect pattern? No. But it should make getting there a little easier to do.
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The engine is still beholden to the laws of physics. Our electric brothers are not.
I don't think you mean quite what you said. Until God reaches down from heaven and touches what we're doing, we're all limited by the laws of physics. They just apply differently in the case of electric power.
I had a discussion with a helicopter-flying club-mate about this sort of thing, and he came up with a very helicopter-pilot sort of suggestion: use an engine that's actively regulated for constant speed, and a variable-pitch prop.
No, I don't know if it'd even start to be worth the extra weight and complexity.
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: use an engine that's actively regulated for constant speed, and a variable-pitch prop.
Now that is a cool idea! I have seen the 4D foam planes fly and they can do some crazy stuff. Imagine being able to fly down to 5 foot super slow then accelerate out of the corner. It may be pretty difficult now that I think about it but you could certainly slow it down quite a bit. Pretty much what Paul was getting with his but you could possibly get a little more with the variable-pitch prop.
Derek
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I don't think you mean quite what you said. Until God reaches down from heaven and touches what we're doing, we're all limited by the laws of physics. They just apply differently in the case of electric power.
Yeah, what I meant was when you add load, IE pointing the nose up, to a 2s motor is will break. The electric motor will not do the same thing. In fact with no governor in place it should slow down a little. With a gov in place it will maintain RPM no matter what the plane is doing. The plane and the motor are separate in that one is changing many things while the other is doing all it can to no change anything one tiny bit. The accelerometer brings the two together again.
I had a discussion with a helicopter-flying club-mate about this sort of thing, and he came up with a very helicopter-pilot sort of suggestion: use an engine that's actively regulated for constant speed, and a variable-pitch prop.
No, I don't know if it'd even start to be worth the extra weight and complexity.
HAHA!! Now you are talking, BRO!!! That's how they fly all that 3D stuff with accuracy and the ability to stop on a dime and start again. It's all in the blades. The motor/headspeed is constant never changing. Their governors are pretty dang quick and can regulate very fast to keep things at a contant motor/head speed. OK, so who's gonna try it first??
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HAHA!! Now you are talking, BRO!!! That's how they fly all that 3D stuff with accuracy and the ability to stop on a dime and start again. It's all in the blades. The motor/headspeed is constant never changing. Their governors are pretty dang quick and can regulate very fast to keep things at a contant motor/head speed. OK, so who's gonna try it first??
Come to think -- does anyone already make an assembly for an IC engine? If so, then way more than half the work is done.
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Finally, a real world use for accelerometers that makes sense. Can't wait to upgrade my phone. And think of the sales potential, all the people dropping their phones just to hear it scream...
EricV
(http://imgs.xkcd.com/comics/xkcd_phone.png)
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A little (very little) update on testing Briddled Thunder. Too windy to fly this morning so mowed some a took along my engine test stand to the field to finally try out the variable Venturi on the .61 Jett. First thing I noticed was the engine was already in a solid two before I got anywhere near my launch RPM. The ID is small so I'll need to bore it out to what I'm using for my regular set up. This requires use of a remote needle. This showed no problems and gave a wide and smooth range of adjustment. This will narrow when I bore the Venturi out. The engine would reliably idle down to only about 4000 rpm. It may be enough for a idle-up launch. The thing I most wanted to know was how much range I could expect for instant response without much dwell time. I'd say 500 rpm is pretty much instant up or down. That should be plenty for active regulation. At a certain needle setting that got me from a solid four to a solid two and back. This was done without pipe. Don't know yet what that will do.
My thinking for now is that my time until the Nats will be better spent on practice than on tinkering and since I'll be using a .76 this time, further work with the accelerometer and the .61 will need to wait until after. I might well be using the timer though.
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Dave have been by the field and see that you have mowed the perimeter and a take off section. Need to get off my duff and get the rider out there. But, Thursdays is spent at the clinic getting the injections in the knees. Two more weeks of them and then Brodaks. School will be out and maybe I can get out to mow more than I have. Yes it has been windy on the days I can fly. But, was told I should not go flying alone anymore, But do I listen.
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John I got it all mowed yesterday. The mower blew up last week and had to buy a new one but back in business. Get out and get ready for the contest! Thinking my next chance with work will be late Friday. Nothing else I'll see you in Topeka Sunday. Kevin crashed the Stuntman last weekend so he may finally be flying the Trivial Pursuit he built like 4-5 years ago and never flew. See ya!
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Kevin (Prier) sent me this shot this morning of his new machine coming along. It's his first self-design and is loosely patterned after a P40. Originally set up for the FP40 but recently changed over to RO Jett .40 with rear exhaust muffler. I really am looking forward to seeing this one fly.
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Don't tell him the old DOC says it looks great. Don't want him to get big headed.